diff --git a/lib/cursor/changeStream.js b/lib/cursor/changeStream.js
index ec5cac5705f..55cdecfcdc2 100644
--- a/lib/cursor/changeStream.js
+++ b/lib/cursor/changeStream.js
@@ -33,15 +33,18 @@ class ChangeStream extends EventEmitter {
       );
     }
 
-    // This wrapper is necessary because of buffering.
-    changeStreamThunk((err, driverChangeStream) => {
-      if (err != null) {
-        this.emit('error', err);
-        return;
-      }
+    this.$driverChangeStreamPromise = new Promise((resolve, reject) => {
+      // This wrapper is necessary because of buffering.
+      changeStreamThunk((err, driverChangeStream) => {
+        if (err != null) {
+          this.emit('error', err);
+          return reject(err);
+        }
 
-      this.driverChangeStream = driverChangeStream;
-      this.emit('ready');
+        this.driverChangeStream = driverChangeStream;
+        this.emit('ready');
+        resolve();
+      });
     });
   }
 
@@ -53,20 +56,23 @@ class ChangeStream extends EventEmitter {
     this.bindedEvents = true;
 
     if (this.driverChangeStream == null) {
-      this.once('ready', () => {
-        this.driverChangeStream.on('close', () => {
-          this.closed = true;
-        });
+      this.$driverChangeStreamPromise.then(
+        () => {
+          this.driverChangeStream.on('close', () => {
+            this.closed = true;
+          });
 
-        driverChangeStreamEvents.forEach(ev => {
-          this.driverChangeStream.on(ev, data => {
-            if (data != null && data.fullDocument != null && this.options && this.options.hydrate) {
-              data.fullDocument = this.options.model.hydrate(data.fullDocument);
-            }
-            this.emit(ev, data);
+          driverChangeStreamEvents.forEach(ev => {
+            this.driverChangeStream.on(ev, data => {
+              if (data != null && data.fullDocument != null && this.options && this.options.hydrate) {
+                data.fullDocument = this.options.model.hydrate(data.fullDocument);
+              }
+              this.emit(ev, data);
+            });
           });
-        });
-      });
+        },
+        () => {} // No need to register events if opening change stream failed
+      );
 
       return;
     }
@@ -142,8 +148,12 @@ class ChangeStream extends EventEmitter {
     this.closed = true;
     if (this.driverChangeStream) {
       return this.driverChangeStream.close();
+    } else {
+      return this.$driverChangeStreamPromise.then(
+        () => this.driverChangeStream.close(),
+        () => {} // No need to close if opening the change stream failed
+      );
     }
-    return Promise.resolve();
   }
 }
 
diff --git a/lib/cursor/queryCursor.js b/lib/cursor/queryCursor.js
index ff59f6aeba8..6f00a316794 100644
--- a/lib/cursor/queryCursor.js
+++ b/lib/cursor/queryCursor.js
@@ -10,6 +10,7 @@ const eachAsync = require('../helpers/cursor/eachAsync');
 const helpers = require('../queryHelpers');
 const kareem = require('kareem');
 const immediate = require('../helpers/immediate');
+const { once } = require('node:events');
 const util = require('util');
 
 /**
@@ -42,6 +43,7 @@ function QueryCursor(query) {
   this.cursor = null;
   this.skipped = false;
   this.query = query;
+  this._closed = false;
   const model = query.model;
   this._mongooseOptions = {};
   this._transforms = [];
@@ -135,6 +137,25 @@ QueryCursor.prototype._read = function() {
   });
 };
 
+/**
+ * Returns the underlying cursor from the MongoDB Node driver that this cursor uses.
+ *
+ * @method getDriverCursor
+ * @memberOf QueryCursor
+ * @returns {Cursor} MongoDB Node driver cursor instance
+ * @instance
+ * @api public
+ */
+
+QueryCursor.prototype.getDriverCursor = async function getDriverCursor() {
+  if (this.cursor) {
+    return this.cursor;
+  }
+
+  await once(this, 'cursor');
+  return this.cursor;
+};
+
 /**
  * Registers a transform function which subsequently maps documents retrieved
  * via the streams interface or `.next()`
@@ -209,6 +230,7 @@ QueryCursor.prototype.close = async function close() {
   }
   try {
     await this.cursor.close();
+    this._closed = true;
     this.emit('close');
   } catch (error) {
     this.listeners('error').length > 0 && this.emit('error', error);
@@ -246,6 +268,9 @@ QueryCursor.prototype.next = async function next() {
   if (typeof arguments[0] === 'function') {
     throw new MongooseError('QueryCursor.prototype.next() no longer accepts a callback');
   }
+  if (this._closed) {
+    throw new MongooseError('Cannot call `next()` on a closed cursor');
+  }
   return new Promise((resolve, reject) => {
     _next(this, function(error, doc) {
       if (error) {
diff --git a/lib/model.js b/lib/model.js
index e0270872155..e83a61be4ff 100644
--- a/lib/model.js
+++ b/lib/model.js
@@ -2115,17 +2115,21 @@ Model.countDocuments = function countDocuments(conditions, options) {
  *
  * @param {String} field
  * @param {Object} [conditions] optional
+ * @param {Object} [options] optional
  * @return {Query}
  * @api public
  */
 
-Model.distinct = function distinct(field, conditions) {
+Model.distinct = function distinct(field, conditions, options) {
   _checkContext(this, 'distinct');
-  if (typeof arguments[0] === 'function' || typeof arguments[1] === 'function') {
+  if (typeof arguments[0] === 'function' || typeof arguments[1] === 'function' || typeof arguments[2] === 'function') {
     throw new MongooseError('Model.distinct() no longer accepts a callback');
   }
 
   const mq = new this.Query({}, {}, this, this.$__collection);
+  if (options != null) {
+    mq.setOptions(options);
+  }
 
   return mq.distinct(field, conditions);
 };
diff --git a/lib/query.js b/lib/query.js
index f928ca75375..dec846a2dcb 100644
--- a/lib/query.js
+++ b/lib/query.js
@@ -2777,7 +2777,7 @@ Query.prototype.estimatedDocumentCount = function(options) {
   this.op = 'estimatedDocumentCount';
   this._validateOp();
 
-  if (typeof options === 'object' && options != null) {
+  if (options != null) {
     this.setOptions(options);
   }
 
@@ -2836,7 +2836,7 @@ Query.prototype.countDocuments = function(conditions, options) {
     this.merge(conditions);
   }
 
-  if (typeof options === 'object' && options != null) {
+  if (options != null) {
     this.setOptions(options);
   }
 
@@ -2874,21 +2874,24 @@ Query.prototype.__distinct = async function __distinct() {
  *
  * #### Example:
  *
+ *     distinct(field, conditions, options)
  *     distinct(field, conditions)
  *     distinct(field)
  *     distinct()
  *
  * @param {String} [field]
  * @param {Object|Query} [filter]
+ * @param {Object} [options]
  * @return {Query} this
  * @see distinct https://www.mongodb.com/docs/manual/reference/method/db.collection.distinct/
  * @api public
  */
 
-Query.prototype.distinct = function(field, conditions) {
+Query.prototype.distinct = function(field, conditions, options) {
   if (typeof field === 'function' ||
       typeof conditions === 'function' ||
-      typeof arguments[2] === 'function') {
+      typeof options === 'function' ||
+      typeof arguments[3] === 'function') {
     throw new MongooseError('Query.prototype.distinct() no longer accepts a callback');
   }
 
@@ -2907,6 +2910,10 @@ Query.prototype.distinct = function(field, conditions) {
     this._distinct = field;
   }
 
+  if (options != null) {
+    this.setOptions(options);
+  }
+
   return this;
 };
 
diff --git a/package.json b/package.json
index 53551cff5c0..0453893604b 100644
--- a/package.json
+++ b/package.json
@@ -21,7 +21,7 @@
   "dependencies": {
     "bson": "^6.7.0",
     "kareem": "2.6.3",
-    "mongodb": "6.7.0",
+    "mongodb": "6.8.0",
     "mpath": "0.9.0",
     "mquery": "5.0.0",
     "ms": "2.1.3",
diff --git a/test/connection.test.js b/test/connection.test.js
index d395be5511b..03f87b40f3d 100644
--- a/test/connection.test.js
+++ b/test/connection.test.js
@@ -1032,6 +1032,8 @@ describe('connections:', function() {
     await nextChange;
     assert.equal(changes.length, 1);
     assert.equal(changes[0].operationType, 'insert');
+
+    await changeStream.close();
     await conn.close();
   });
 
diff --git a/test/docs/transactions.test.js b/test/docs/transactions.test.js
index 2b19aef9ee3..de2ecfc9952 100644
--- a/test/docs/transactions.test.js
+++ b/test/docs/transactions.test.js
@@ -338,6 +338,25 @@ describe('transactions', function() {
     assert.deepEqual(fromDb, { name: 'Tyrion Lannister' });
   });
 
+  it('distinct (gh-8006)', async function() {
+    const Character = db.model('gh8006_Character', new Schema({ name: String, rank: String }, { versionKey: false }));
+
+    const session = await db.startSession();
+
+    session.startTransaction();
+    await Character.create([{ name: 'Will Riker', rank: 'Commander' }, { name: 'Jean-Luc Picard', rank: 'Captain' }], { session });
+
+    let names = await Character.distinct('name', {}, { session });
+    assert.deepStrictEqual(names.sort(), ['Jean-Luc Picard', 'Will Riker']);
+
+    names = await Character.distinct('name', { rank: 'Captain' }, { session });
+    assert.deepStrictEqual(names.sort(), ['Jean-Luc Picard']);
+
+    // Undo both update and delete since doc should pull from `$session()`
+    await session.abortTransaction();
+    session.endSession();
+  });
+
   it('save() with no changes (gh-8571)', async function() {
     db.deleteModel(/Test/);
     const Test = db.model('Test', Schema({ name: String }));
diff --git a/test/model.test.js b/test/model.test.js
index 855f1eecb8f..f6943d96fc7 100644
--- a/test/model.test.js
+++ b/test/model.test.js
@@ -7,6 +7,7 @@ const sinon = require('sinon');
 const start = require('./common');
 
 const assert = require('assert');
+const { once } = require('events');
 const random = require('./util').random;
 const util = require('./util');
 
@@ -3508,6 +3509,9 @@ describe('Model', function() {
           }
           changeStream.removeListener('change', listener);
           listener = null;
+          // Change stream may still emit "MongoAPIError: ChangeStream is closed" because change stream
+          // may still poll after close.
+          changeStream.on('error', () => {});
           changeStream.close();
           changeStream = null;
         });
@@ -3560,14 +3564,21 @@ describe('Model', function() {
         it('fullDocument (gh-11936)', async function() {
           const MyModel = db.model('Test', new Schema({ name: String }));
 
+          const doc = await MyModel.create({ name: 'Ned Stark' });
           const changeStream = await MyModel.watch([], {
             fullDocument: 'updateLookup',
             hydrate: true
           });
+          await changeStream.$driverChangeStreamPromise;
 
-          const doc = await MyModel.create({ name: 'Ned Stark' });
-
-          const p = changeStream.next();
+          const p = new Promise((resolve) => {
+            changeStream.once('change', change => {
+              resolve(change);
+            });
+          });
+          // Need to wait for resume token to be set after the event listener,
+          // otherwise change stream might not pick up the update.
+          await once(changeStream.driverChangeStream, 'resumeTokenChanged');
           await MyModel.updateOne({ _id: doc._id }, { name: 'Tony Stark' });
 
           const changeData = await p;
@@ -3576,6 +3587,8 @@ describe('Model', function() {
             doc._id.toHexString());
           assert.ok(changeData.fullDocument.$__);
           assert.equal(changeData.fullDocument.get('name'), 'Tony Stark');
+
+          await changeStream.close();
         });
 
         it('fullDocument with immediate watcher and hydrate (gh-14049)', async function() {
@@ -3583,15 +3596,22 @@ describe('Model', function() {
 
           const doc = await MyModel.create({ name: 'Ned Stark' });
 
+          let changeStream = null;
           const p = new Promise((resolve) => {
-            MyModel.watch([], {
+            changeStream = MyModel.watch([], {
               fullDocument: 'updateLookup',
               hydrate: true
-            }).on('change', change => {
+            });
+
+            changeStream.on('change', change => {
               resolve(change);
             });
           });
 
+          // Need to wait for cursor to be initialized and for resume token to
+          // be set, otherwise change stream might not pick up the update.
+          await changeStream.$driverChangeStreamPromise;
+          await once(changeStream.driverChangeStream, 'resumeTokenChanged');
           await MyModel.updateOne({ _id: doc._id }, { name: 'Tony Stark' });
 
           const changeData = await p;
@@ -3600,6 +3620,8 @@ describe('Model', function() {
             doc._id.toHexString());
           assert.ok(changeData.fullDocument.$__);
           assert.equal(changeData.fullDocument.get('name'), 'Tony Stark');
+
+          await changeStream.close();
         });
 
         it('respects discriminators (gh-11007)', async function() {
@@ -3639,6 +3661,9 @@ describe('Model', function() {
           assert.equal(changeData.operationType, 'insert');
           assert.equal(changeData.fullDocument.name, 'Ned Stark');
 
+          // Change stream may still emit "MongoAPIError: ChangeStream is closed" because change stream
+          // may still poll after close.
+          changeStream.on('error', () => {});
           await changeStream.close();
           await db.close();
         });
@@ -3654,11 +3679,16 @@ describe('Model', function() {
             setTimeout(resolve, 500, false);
           });
 
-          changeStream.close();
-          await db;
+          // Change stream may still emit "MongoAPIError: ChangeStream is closed" because change stream
+          // may still poll after close.
+          changeStream.on('error', () => {});
+
+          const close = changeStream.close();
+          await db.asPromise();
           const readyCalled = await ready;
           assert.strictEqual(readyCalled, false);
 
+          await close;
           await db.close();
         });
 
@@ -3675,6 +3705,10 @@ describe('Model', function() {
 
           await MyModel.create({ name: 'Hodor' });
 
+          // Change stream may still emit "MongoAPIError: ChangeStream is closed" because change stream
+          // may still poll after close.
+          changeStream.on('error', () => {});
+
           changeStream.close();
           const closedData = await closed;
           assert.strictEqual(closedData, true);
diff --git a/test/model.watch.test.js b/test/model.watch.test.js
index 84d41dc5b14..3e2ad733a24 100644
--- a/test/model.watch.test.js
+++ b/test/model.watch.test.js
@@ -37,18 +37,22 @@ describe('model: watch: ', function() {
       const changeData = await changed;
       assert.equal(changeData.operationType, 'insert');
       assert.equal(changeData.fullDocument.name, 'Ned Stark');
+      await changeStream.close();
     });
 
     it('watch() close() prevents buffered watch op from running (gh-7022)', async function() {
       const MyModel = db.model('Test', new Schema({}));
       const changeStream = MyModel.watch();
-      const ready = new global.Promise(resolve => {
+      const ready = new Promise(resolve => {
         changeStream.once('data', () => {
           resolve(true);
         });
         setTimeout(resolve, 500, false);
       });
 
+      // Change stream may still emit "MongoAPIError: ChangeStream is closed" because change stream
+      // may still poll after close.
+      changeStream.on('error', () => {});
       const close = changeStream.close();
       await db.asPromise();
       const readyCalled = await ready;
@@ -64,12 +68,16 @@ describe('model: watch: ', function() {
       await MyModel.init();
 
       const changeStream = MyModel.watch();
-      const closed = new global.Promise(resolve => {
+      const closed = new Promise(resolve => {
         changeStream.once('close', () => resolve(true));
       });
 
       await MyModel.create({ name: 'Hodor' });
 
+      // Change stream may still emit "MongoAPIError: ChangeStream is closed" because change stream
+      // may still poll after close.
+      changeStream.on('error', () => {});
+
       await changeStream.close();
 
       const closedData = await closed;
diff --git a/test/query.cursor.test.js b/test/query.cursor.test.js
index d835135a0b2..d80264c5f2d 100644
--- a/test/query.cursor.test.js
+++ b/test/query.cursor.test.js
@@ -415,7 +415,8 @@ describe('QueryCursor', function() {
         await cursor.next();
         assert.ok(false);
       } catch (error) {
-        assert.equal(error.name, 'MongoCursorExhaustedError');
+        assert.equal(error.name, 'MongooseError');
+        assert.ok(error.message.includes('closed cursor'), error.message);
       }
     });
   });
@@ -900,6 +901,25 @@ describe('QueryCursor', function() {
     assert.ok(err);
     assert.ok(err.message.includes('skipMiddlewareFunction'), err.message);
   });
+
+  it('returns the underlying Node driver cursor with getDriverCursor()', async function() {
+    const schema = new mongoose.Schema({ name: String });
+
+    const Movie = db.model('Movie', schema);
+
+    await Movie.deleteMany({});
+    await Movie.create([
+      { name: 'Kickboxer' },
+      { name: 'Ip Man' },
+      { name: 'Enter the Dragon' }
+    ]);
+
+    const cursor = await Movie.find({}).cursor();
+    assert.ok(!cursor.cursor);
+    const driverCursor = await cursor.getDriverCursor();
+    assert.ok(cursor.cursor);
+    assert.equal(driverCursor, cursor.cursor);
+  });
 });
 
 async function delay(ms) {
diff --git a/test/query.test.js b/test/query.test.js
index bf6175e0688..a3de50044e3 100644
--- a/test/query.test.js
+++ b/test/query.test.js
@@ -1088,6 +1088,16 @@ describe('Query', function() {
 
       assert.equal(q.op, 'distinct');
     });
+
+    it('using options parameter for distinct', function() {
+      const q = new Query({});
+      const options = { collation: { locale: 'en', strength: 2 } };
+
+      q.distinct('blah', {}, options);
+
+      assert.equal(q.op, 'distinct');
+      assert.deepEqual(q.options.collation, options.collation);
+    });
   });
 
   describe('findOne', function() {
diff --git a/test/types/docArray.test.ts b/test/types/docArray.test.ts
index c296ce6fea7..78650845ba2 100644
--- a/test/types/docArray.test.ts
+++ b/test/types/docArray.test.ts
@@ -91,7 +91,7 @@ async function gh13424() {
   const TestModel = model('Test', testSchema);
 
   const doc = new TestModel();
-  expectType<Types.ObjectId | undefined>(doc.subDocArray[0]._id);
+  expectType<Types.ObjectId>(doc.subDocArray[0]._id);
 }
 
 async function gh14367() {
diff --git a/test/types/document.test.ts b/test/types/document.test.ts
index d492cebd6e7..84451edf0f2 100644
--- a/test/types/document.test.ts
+++ b/test/types/document.test.ts
@@ -10,7 +10,7 @@ import {
   DefaultSchemaOptions
 } from 'mongoose';
 import { DeleteResult } from 'mongodb';
-import { expectAssignable, expectError, expectType } from 'tsd';
+import { expectAssignable, expectError, expectNotAssignable, expectType } from 'tsd';
 import { autoTypedModel } from './models.test';
 import { autoTypedModelConnection } from './connection.test';
 import { AutoTypedSchemaType } from './schema.test';
@@ -42,7 +42,8 @@ void async function main() {
 
   expectType<DeleteResult>(await doc.deleteOne());
   expectType<TestDocument | null>(await doc.deleteOne().findOne());
-  expectType<{ _id: Types.ObjectId, name?: string } | null>(await doc.deleteOne().findOne().lean());
+  expectAssignable<{ _id: Types.ObjectId, name?: string } | null>(await doc.deleteOne().findOne().lean());
+  expectNotAssignable<TestDocument | null>(await doc.deleteOne().findOne().lean());
 }();
 
 
diff --git a/test/types/models.test.ts b/test/types/models.test.ts
index 218c4c90569..fbe411225f0 100644
--- a/test/types/models.test.ts
+++ b/test/types/models.test.ts
@@ -215,8 +215,8 @@ function find() {
   Project.find({});
   Project.find({ name: 'Hello' });
 
-  // just callback
-  Project.find((error: CallbackError, result: IProject[]) => console.log(error, result));
+  // just callback; this is no longer supported on .find()
+  expectError(Project.find((error: CallbackError, result: IProject[]) => console.log(error, result)));
 
   // filter + projection
   Project.find({}, undefined);
@@ -977,3 +977,29 @@ function testWithLevel1NestedPaths() {
     'foo.one': string | null | undefined
   }>({} as Test2);
 }
+
+function gh14764TestFilterQueryRestrictions() {
+  const TestModel = model<{ validKey: number }>('Test', new Schema({}));
+  // A key not in the schema should be invalid
+  expectError(TestModel.find({ invalidKey: 0 }));
+  // A key not in the schema should be invalid for simple root operators
+  expectError(TestModel.find({ $and: [{ invalidKey: 0 }] }));
+
+  // Any "nested" keys should be valid
+  TestModel.find({ 'validKey.subkey': 0 });
+
+  // And deeply "nested" keys should be valid
+  TestModel.find({ 'validKey.deep.nested.key': 0 });
+  TestModel.find({ validKey: { deep: { nested: { key: 0 } } } });
+
+  // Any Query should be accepted as the root argument (due to merge support)
+  TestModel.find(TestModel.find());
+  // A Query should not be a valid type for a FilterQuery within an op like $and
+  expectError(TestModel.find({ $and: [TestModel.find()] }));
+
+  const id = new Types.ObjectId();
+  // Any ObjectId should be accepted as the root argument
+  TestModel.find(id);
+  // A ObjectId should not be a valid type for a FilterQuery within an op like $and
+  expectError(TestModel.find({ $and: [id] }));
+}
diff --git a/test/types/plugin.test.ts b/test/types/plugin.test.ts
index 0b579ccc6b9..fc1deddf900 100644
--- a/test/types/plugin.test.ts
+++ b/test/types/plugin.test.ts
@@ -49,7 +49,7 @@ interface TestStaticMethods {
   findSomething(this: TestModel): Promise<TestDocument>;
 }
 type TestDocument = HydratedDocument<Test, TestVirtuals & TestInstanceMethods>;
-type TestQuery = Query<any, TestDocument, TestQueryHelpers> & TestQueryHelpers;
+type TestQuery = Query<any, TestDocument, TestQueryHelpers, Test> & TestQueryHelpers;
 interface TestQueryHelpers {
   whereSomething(this: TestQuery): this
 }
diff --git a/test/types/queries.test.ts b/test/types/queries.test.ts
index f10f26b3ad2..5396f384cad 100644
--- a/test/types/queries.test.ts
+++ b/test/types/queries.test.ts
@@ -38,11 +38,11 @@ const schema: Schema<ITest, Model<ITest, QueryHelpers>, {}, QueryHelpers> = new
   endDate: Date
 });
 
-schema.query._byName = function(name: string): QueryWithHelpers<any, ITest, QueryHelpers> {
+schema.query._byName = function(name: string): QueryWithHelpers<ITest[], ITest, QueryHelpers> {
   return this.find({ name });
 };
 
-schema.query.byName = function(name: string): QueryWithHelpers<any, ITest, QueryHelpers> {
+schema.query.byName = function(name: string): QueryWithHelpers<ITest[], ITest, QueryHelpers> {
   expectError(this.notAQueryHelper());
   return this._byName(name);
 };
@@ -109,6 +109,7 @@ Test.find({ name: { $gte: 'Test' } }, null, { collation: { locale: 'en-us' } }).
 Test.findOne().orFail(new Error('bar')).then((doc: ITest | null) => console.log('Found! ' + doc));
 
 Test.distinct('name').exec().then((res: Array<any>) => console.log(res[0]));
+Test.distinct('name', {}, { collation: { locale: 'en', strength: 2 } }).exec().then((res: Array<any>) => console.log(res[0]));
 
 Test.findOneAndUpdate({ name: 'test' }, { name: 'test2' }).exec().then((res: ITest | null) => console.log(res));
 Test.findOneAndUpdate({ name: 'test' }, { name: 'test2' }).then((res: ITest | null) => console.log(res));
diff --git a/test/types/queryhelpers.test.ts b/test/types/queryhelpers.test.ts
index c96aaffbaa2..34a55b6bd22 100644
--- a/test/types/queryhelpers.test.ts
+++ b/test/types/queryhelpers.test.ts
@@ -8,7 +8,7 @@ interface Project {
 type ProjectModelType = Model<Project, ProjectQueryHelpers>;
 // Query helpers should return `Query<any, Document<DocType>> & ProjectQueryHelpers`
 // to enable chaining.
-type ProjectModelQuery = Query<any, HydratedDocument<Project>, ProjectQueryHelpers> & ProjectQueryHelpers;
+type ProjectModelQuery = Query<any, HydratedDocument<Project>, ProjectQueryHelpers, any> & ProjectQueryHelpers;
 interface ProjectQueryHelpers {
   byName(this: ProjectModelQuery, name: string): ProjectModelQuery;
 }
diff --git a/test/types/schema.test.ts b/test/types/schema.test.ts
index 8c9d1a8f3d5..04828bc4f17 100644
--- a/test/types/schema.test.ts
+++ b/test/types/schema.test.ts
@@ -22,6 +22,7 @@ import {
   model,
   ValidateOpts
 } from 'mongoose';
+import { IsPathRequired } from '../../types/inferschematype';
 import { expectType, expectError, expectAssignable } from 'tsd';
 import { ObtainDocumentPathType, ResolvePathType } from '../../types/inferschematype';
 
@@ -1387,7 +1388,7 @@ function gh13424() {
   const TestModel = model('TestModel', new Schema(testSchema));
 
   const doc = new TestModel({});
-  expectType<Types.ObjectId | undefined>(doc.subDocArray[0]._id);
+  expectType<Types.ObjectId>(doc.subDocArray[0]._id);
 }
 
 function gh14147() {
@@ -1502,16 +1503,18 @@ function gh13772() {
   const schemaDefinition = {
     name: String,
     docArr: [{ name: String }]
-  };
+  } as const;
   const schema = new Schema(schemaDefinition);
+
+  const TestModel = model('User', schema);
   type RawDocType = InferRawDocType<typeof schemaDefinition>;
   expectAssignable<
-    { name?: string | null, docArr?: Array<{ name?: string | null }> }
+    { name?: string | null, docArr?: Array<{ name?: string | null }> | null }
   >({} as RawDocType);
 
-  const TestModel = model('User', schema);
   const doc = new TestModel();
   expectAssignable<RawDocType>(doc.toObject());
+  expectAssignable<RawDocType>(doc.toJSON());
 }
 
 function gh14696() {
diff --git a/types/document.d.ts b/types/document.d.ts
index c0fb5589240..5557269783f 100644
--- a/types/document.d.ts
+++ b/types/document.d.ts
@@ -22,7 +22,7 @@ declare module 'mongoose' {
     constructor(doc?: any);
 
     /** This documents _id. */
-    _id?: T;
+    _id: T;
 
     /** This documents __v. */
     __v?: any;
@@ -259,11 +259,14 @@ declare module 'mongoose' {
     set(value: string | Record<string, any>): this;
 
     /** The return value of this method is used in calls to JSON.stringify(doc). */
+    toJSON(options?: ToObjectOptions & { flattenMaps?: true }): FlattenMaps<Require_id<DocType>>;
+    toJSON(options: ToObjectOptions & { flattenMaps: false }): Require_id<DocType>;
     toJSON<T = Require_id<DocType>>(options?: ToObjectOptions & { flattenMaps?: true }): FlattenMaps<T>;
     toJSON<T = Require_id<DocType>>(options: ToObjectOptions & { flattenMaps: false }): T;
 
     /** Converts this document into a plain-old JavaScript object ([POJO](https://masteringjs.io/tutorials/fundamentals/pojo)). */
-    toObject<T = Require_id<DocType>>(options?: ToObjectOptions): Require_id<T>;
+    toObject(options?: ToObjectOptions): Require_id<DocType>;
+    toObject<T>(options?: ToObjectOptions): Require_id<T>;
 
     /** Clears the modified state on the specified path. */
     unmarkModified<T extends keyof DocType>(path: T): void;
diff --git a/types/inferrawdoctype.d.ts b/types/inferrawdoctype.d.ts
index e2b1d52b6b9..5ef52e13251 100644
--- a/types/inferrawdoctype.d.ts
+++ b/types/inferrawdoctype.d.ts
@@ -1,4 +1,5 @@
 import {
+  IsPathRequired,
   IsSchemaTypeFromBuiltinClass,
   RequiredPaths,
   OptionalPaths,
@@ -14,7 +15,9 @@ declare module 'mongoose' {
     [
     K in keyof (RequiredPaths<DocDefinition, TSchemaOptions['typeKey']> &
     OptionalPaths<DocDefinition, TSchemaOptions['typeKey']>)
-    ]: ObtainRawDocumentPathType<DocDefinition[K], TSchemaOptions['typeKey']>;
+    ]: IsPathRequired<DocDefinition[K], TSchemaOptions['typeKey']> extends true
+      ? ObtainRawDocumentPathType<DocDefinition[K], TSchemaOptions['typeKey']>
+      : ObtainRawDocumentPathType<DocDefinition[K], TSchemaOptions['typeKey']> | null;
   }, TSchemaOptions>;
 
   /**
diff --git a/types/models.d.ts b/types/models.d.ts
index 27c43612ac2..4c2403fd51b 100644
--- a/types/models.d.ts
+++ b/types/models.d.ts
@@ -188,7 +188,7 @@ declare module 'mongoose' {
 
   export interface ReplaceOneModel<TSchema = AnyObject> {
     /** The filter to limit the replaced document. */
-    filter: FilterQuery<TSchema>;
+    filter: RootFilterQuery<TSchema>;
     /** The document with which to replace the matched document. */
     replacement: mongodb.WithoutId<TSchema>;
     /** Specifies a collation. */
@@ -203,7 +203,7 @@ declare module 'mongoose' {
 
   export interface UpdateOneModel<TSchema = AnyObject> {
     /** The filter to limit the updated documents. */
-    filter: FilterQuery<TSchema>;
+    filter: RootFilterQuery<TSchema>;
     /** A document or pipeline containing update operators. */
     update: UpdateQuery<TSchema>;
     /** A set of filters specifying to which array elements an update should apply. */
@@ -220,7 +220,7 @@ declare module 'mongoose' {
 
   export interface UpdateManyModel<TSchema = AnyObject> {
     /** The filter to limit the updated documents. */
-    filter: FilterQuery<TSchema>;
+    filter: RootFilterQuery<TSchema>;
     /** A document or pipeline containing update operators. */
     update: UpdateQuery<TSchema>;
     /** A set of filters specifying to which array elements an update should apply. */
@@ -237,7 +237,7 @@ declare module 'mongoose' {
 
   export interface DeleteOneModel<TSchema = AnyObject> {
     /** The filter to limit the deleted documents. */
-    filter: FilterQuery<TSchema>;
+    filter: RootFilterQuery<TSchema>;
     /** Specifies a collation. */
     collation?: mongodb.CollationOptions;
     /** The index to use. If specified, then the query system will only consider plans using the hinted index. */
@@ -246,7 +246,7 @@ declare module 'mongoose' {
 
   export interface DeleteManyModel<TSchema = AnyObject> {
     /** The filter to limit the deleted documents. */
-    filter: FilterQuery<TSchema>;
+    filter: RootFilterQuery<TSchema>;
     /** Specifies a collation. */
     collation?: mongodb.CollationOptions;
     /** The index to use. If specified, then the query system will only consider plans using the hinted index. */
@@ -318,7 +318,7 @@ declare module 'mongoose' {
 
     /** Creates a `countDocuments` query: counts the number of documents that match `filter`. */
     countDocuments(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       options?: (mongodb.CountOptions & MongooseBaseQueryOptions<TRawDocType>) | null
     ): QueryWithHelpers<
       number,
@@ -357,7 +357,7 @@ declare module 'mongoose' {
      * regardless of the `single` option.
      */
     deleteMany(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       options?: (mongodb.DeleteOptions & MongooseBaseQueryOptions<TRawDocType>) | null
     ): QueryWithHelpers<
       mongodb.DeleteResult,
@@ -368,7 +368,7 @@ declare module 'mongoose' {
       TInstanceMethods
     >;
     deleteMany(
-      filter: FilterQuery<TRawDocType>
+      filter: RootFilterQuery<TRawDocType>
     ): QueryWithHelpers<
       mongodb.DeleteResult,
       THydratedDocumentType,
@@ -384,7 +384,7 @@ declare module 'mongoose' {
      * `single` option.
      */
     deleteOne(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       options?: (mongodb.DeleteOptions & MongooseBaseQueryOptions<TRawDocType>) | null
     ): QueryWithHelpers<
       mongodb.DeleteResult,
@@ -395,7 +395,7 @@ declare module 'mongoose' {
       TInstanceMethods
     >;
     deleteOne(
-      filter: FilterQuery<TRawDocType>
+      filter: RootFilterQuery<TRawDocType>
     ): QueryWithHelpers<
       mongodb.DeleteResult,
       THydratedDocumentType,
@@ -446,7 +446,7 @@ declare module 'mongoose' {
 
     /** Finds one document. */
     findOne<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       projection: ProjectionType<TRawDocType> | null | undefined,
       options: QueryOptions<TRawDocType> & { lean: true }
     ): QueryWithHelpers<
@@ -458,16 +458,16 @@ declare module 'mongoose' {
       TInstanceMethods
     >;
     findOne<ResultDoc = THydratedDocumentType>(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       projection?: ProjectionType<TRawDocType> | null,
       options?: QueryOptions<TRawDocType> | null
     ): QueryWithHelpers<ResultDoc | null, ResultDoc, TQueryHelpers, TRawDocType, 'findOne', TInstanceMethods>;
     findOne<ResultDoc = THydratedDocumentType>(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       projection?: ProjectionType<TRawDocType> | null
     ): QueryWithHelpers<ResultDoc | null, ResultDoc, TQueryHelpers, TRawDocType, 'findOne', TInstanceMethods>;
     findOne<ResultDoc = THydratedDocumentType>(
-      filter?: FilterQuery<TRawDocType>
+      filter?: RootFilterQuery<TRawDocType>
     ): QueryWithHelpers<ResultDoc | null, ResultDoc, TQueryHelpers, TRawDocType, 'findOne', TInstanceMethods>;
 
     /**
@@ -621,7 +621,8 @@ declare module 'mongoose' {
     /** Creates a `distinct` query: returns the distinct values of the given `field` that match `filter`. */
     distinct<DocKey extends string, ResultType = unknown>(
       field: DocKey,
-      filter?: FilterQuery<TRawDocType>
+      filter?: RootFilterQuery<TRawDocType>,
+      options?: QueryOptions<TRawDocType>
     ): QueryWithHelpers<
       Array<
         DocKey extends keyof WithLevel1NestedPaths<TRawDocType>
@@ -650,7 +651,7 @@ declare module 'mongoose' {
      * the given `filter`, and `null` otherwise.
      */
     exists(
-      filter: FilterQuery<TRawDocType>
+      filter: RootFilterQuery<TRawDocType>
     ): QueryWithHelpers<
       { _id: InferId<TRawDocType> } | null,
       THydratedDocumentType,
@@ -662,7 +663,7 @@ declare module 'mongoose' {
 
     /** Creates a `find` query: gets a list of documents that match `filter`. */
     find<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       projection: ProjectionType<TRawDocType> | null | undefined,
       options: QueryOptions<TRawDocType> & { lean: true }
     ): QueryWithHelpers<
@@ -674,16 +675,16 @@ declare module 'mongoose' {
       TInstanceMethods
     >;
     find<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       projection?: ProjectionType<TRawDocType> | null | undefined,
       options?: QueryOptions<TRawDocType> | null | undefined
     ): QueryWithHelpers<Array<ResultDoc>, ResultDoc, TQueryHelpers, TRawDocType, 'find', TInstanceMethods>;
     find<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       projection?: ProjectionType<TRawDocType> | null | undefined
     ): QueryWithHelpers<Array<ResultDoc>, ResultDoc, TQueryHelpers, TRawDocType, 'find', TInstanceMethods>;
     find<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>
+      filter: RootFilterQuery<TRawDocType>
     ): QueryWithHelpers<Array<ResultDoc>, ResultDoc, TQueryHelpers, TRawDocType, 'find', TInstanceMethods>;
     find<ResultDoc = THydratedDocumentType>(
     ): QueryWithHelpers<Array<ResultDoc>, ResultDoc, TQueryHelpers, TRawDocType, 'find', TInstanceMethods>;
@@ -711,7 +712,7 @@ declare module 'mongoose' {
 
     /** Creates a `findOneAndUpdate` query, filtering by the given `_id`. */
     findByIdAndUpdate<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       update: UpdateQuery<TRawDocType>,
       options: QueryOptions<TRawDocType> & { includeResultMetadata: true, lean: true }
     ): QueryWithHelpers<
@@ -756,7 +757,7 @@ declare module 'mongoose' {
 
     /** Creates a `findOneAndDelete` query: atomically finds the given document, deletes it, and returns the document as it was before deletion. */
     findOneAndDelete<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       options: QueryOptions<TRawDocType> & { lean: true }
     ): QueryWithHelpers<
       GetLeanResultType<TRawDocType, TRawDocType, 'findOneAndDelete'> | null,
@@ -767,17 +768,17 @@ declare module 'mongoose' {
       TInstanceMethods
     >;
     findOneAndDelete<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       options: QueryOptions<TRawDocType> & { includeResultMetadata: true }
     ): QueryWithHelpers<ModifyResult<ResultDoc>, ResultDoc, TQueryHelpers, TRawDocType, 'findOneAndDelete', TInstanceMethods>;
     findOneAndDelete<ResultDoc = THydratedDocumentType>(
-      filter?: FilterQuery<TRawDocType> | null,
+      filter?: RootFilterQuery<TRawDocType> | null,
       options?: QueryOptions<TRawDocType> | null
     ): QueryWithHelpers<ResultDoc | null, ResultDoc, TQueryHelpers, TRawDocType, 'findOneAndDelete', TInstanceMethods>;
 
     /** Creates a `findOneAndReplace` query: atomically finds the given document and replaces it with `replacement`. */
     findOneAndReplace<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       replacement: TRawDocType | AnyObject,
       options: QueryOptions<TRawDocType> & { lean: true }
     ): QueryWithHelpers<
@@ -789,24 +790,24 @@ declare module 'mongoose' {
       TInstanceMethods
     >;
     findOneAndReplace<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       replacement: TRawDocType | AnyObject,
       options: QueryOptions<TRawDocType> & { includeResultMetadata: true }
     ): QueryWithHelpers<ModifyResult<ResultDoc>, ResultDoc, TQueryHelpers, TRawDocType, 'findOneAndReplace', TInstanceMethods>;
     findOneAndReplace<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       replacement: TRawDocType | AnyObject,
       options: QueryOptions<TRawDocType> & { upsert: true } & ReturnsNewDoc
     ): QueryWithHelpers<ResultDoc, ResultDoc, TQueryHelpers, TRawDocType, 'findOneAndReplace', TInstanceMethods>;
     findOneAndReplace<ResultDoc = THydratedDocumentType>(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       replacement?: TRawDocType | AnyObject,
       options?: QueryOptions<TRawDocType> | null
     ): QueryWithHelpers<ResultDoc | null, ResultDoc, TQueryHelpers, TRawDocType, 'findOneAndReplace', TInstanceMethods>;
 
     /** Creates a `findOneAndUpdate` query: atomically find the first document that matches `filter` and apply `update`. */
     findOneAndUpdate<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       update: UpdateQuery<TRawDocType>,
       options: QueryOptions<TRawDocType> & { includeResultMetadata: true, lean: true }
     ): QueryWithHelpers<
@@ -818,7 +819,7 @@ declare module 'mongoose' {
       TInstanceMethods
     >;
     findOneAndUpdate<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       update: UpdateQuery<TRawDocType>,
       options: QueryOptions<TRawDocType> & { lean: true }
     ): QueryWithHelpers<
@@ -830,24 +831,24 @@ declare module 'mongoose' {
       TInstanceMethods
     >;
     findOneAndUpdate<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       update: UpdateQuery<TRawDocType>,
       options: QueryOptions<TRawDocType> & { includeResultMetadata: true }
     ): QueryWithHelpers<ModifyResult<ResultDoc>, ResultDoc, TQueryHelpers, TRawDocType, 'findOneAndUpdate', TInstanceMethods>;
     findOneAndUpdate<ResultDoc = THydratedDocumentType>(
-      filter: FilterQuery<TRawDocType>,
+      filter: RootFilterQuery<TRawDocType>,
       update: UpdateQuery<TRawDocType>,
       options: QueryOptions<TRawDocType> & { upsert: true } & ReturnsNewDoc
     ): QueryWithHelpers<ResultDoc, ResultDoc, TQueryHelpers, TRawDocType, 'findOneAndUpdate', TInstanceMethods>;
     findOneAndUpdate<ResultDoc = THydratedDocumentType>(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       update?: UpdateQuery<TRawDocType>,
       options?: QueryOptions<TRawDocType> | null
     ): QueryWithHelpers<ResultDoc | null, ResultDoc, TQueryHelpers, TRawDocType, 'findOneAndUpdate', TInstanceMethods>;
 
     /** Creates a `replaceOne` query: finds the first document that matches `filter` and replaces it with `replacement`. */
     replaceOne<ResultDoc = THydratedDocumentType>(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       replacement?: TRawDocType | AnyObject,
       options?: (mongodb.ReplaceOptions & MongooseQueryOptions<TRawDocType>) | null
     ): QueryWithHelpers<UpdateWriteOpResult, ResultDoc, TQueryHelpers, TRawDocType, 'replaceOne', TInstanceMethods>;
@@ -860,14 +861,14 @@ declare module 'mongoose' {
 
     /** Creates a `updateMany` query: updates all documents that match `filter` with `update`. */
     updateMany<ResultDoc = THydratedDocumentType>(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       update?: UpdateQuery<TRawDocType> | UpdateWithAggregationPipeline,
       options?: (mongodb.UpdateOptions & MongooseUpdateQueryOptions<TRawDocType>) | null
     ): QueryWithHelpers<UpdateWriteOpResult, ResultDoc, TQueryHelpers, TRawDocType, 'updateMany', TInstanceMethods>;
 
     /** Creates a `updateOne` query: updates the first document that matches `filter` with `update`. */
     updateOne<ResultDoc = THydratedDocumentType>(
-      filter?: FilterQuery<TRawDocType>,
+      filter?: RootFilterQuery<TRawDocType>,
       update?: UpdateQuery<TRawDocType> | UpdateWithAggregationPipeline,
       options?: (mongodb.UpdateOptions & MongooseUpdateQueryOptions<TRawDocType>) | null
     ): QueryWithHelpers<UpdateWriteOpResult, ResultDoc, TQueryHelpers, TRawDocType, 'updateOne', TInstanceMethods>;
diff --git a/types/query.d.ts b/types/query.d.ts
index 58cfe517ce6..572ec33e1df 100644
--- a/types/query.d.ts
+++ b/types/query.d.ts
@@ -10,9 +10,11 @@ declare module 'mongoose' {
    * { age: { $gte: 30 } }
    * ```
    */
-  type FilterQuery<T> = {
+  type RootFilterQuery<T> = FilterQuery<T> | Query<any, any> | Types.ObjectId;
+
+  type FilterQuery<T> ={
     [P in keyof T]?: Condition<T[P]>;
-  } & RootQuerySelector<T>;
+  } & RootQuerySelector<T> & { _id?: Condition<string>; };
 
   type MongooseBaseQueryOptionKeys =
     | 'context'
@@ -115,8 +117,9 @@ declare module 'mongoose' {
     /** @see https://www.mongodb.com/docs/manual/reference/operator/query/comment/#op._S_comment */
     $comment?: string;
     // we could not find a proper TypeScript generic to support nested queries e.g. 'user.friends.name'
-    // this will mark all unrecognized properties as any (including nested queries)
-    [key: string]: any;
+    // this will mark all unrecognized properties as any (including nested queries) only if
+    // they include a "." (to avoid generically allowing any unexpected keys)
+    [nestedSelector: `${string}.${string}`]: any;
   };
 
   interface QueryTimestampsConfig {
@@ -224,7 +227,7 @@ declare module 'mongoose' {
           : MergeType<ResultType, Paths>
     : MergeType<ResultType, Paths>;
 
-  class Query<ResultType, DocType, THelpers = {}, RawDocType = DocType, QueryOp = 'find', TInstanceMethods = Record<string, never>> implements SessionOperation {
+  class Query<ResultType, DocType, THelpers = {}, RawDocType = unknown, QueryOp = 'find', TInstanceMethods = Record<string, never>> implements SessionOperation {
     _mongooseOptions: MongooseQueryOptions<DocType>;
 
     /**
@@ -303,7 +306,7 @@ declare module 'mongoose' {
 
     /** Specifies this query as a `countDocuments` query. */
     countDocuments(
-      criteria?: FilterQuery<RawDocType>,
+      criteria?: RootFilterQuery<RawDocType>,
       options?: QueryOptions<DocType>
     ): QueryWithHelpers<number, DocType, THelpers, RawDocType, 'countDocuments', TInstanceMethods>;
 
@@ -319,10 +322,10 @@ declare module 'mongoose' {
      * collection, regardless of the value of `single`.
      */
     deleteMany(
-      filter?: FilterQuery<RawDocType>,
+      filter?: RootFilterQuery<RawDocType>,
       options?: QueryOptions<DocType>
     ): QueryWithHelpers<any, DocType, THelpers, RawDocType, 'deleteMany', TInstanceMethods>;
-    deleteMany(filter: FilterQuery<RawDocType>): QueryWithHelpers<
+    deleteMany(filter: RootFilterQuery<RawDocType>): QueryWithHelpers<
       any,
       DocType,
       THelpers,
@@ -338,10 +341,10 @@ declare module 'mongoose' {
      * option.
      */
     deleteOne(
-      filter?: FilterQuery<RawDocType>,
+      filter?: RootFilterQuery<RawDocType>,
       options?: QueryOptions<DocType>
     ): QueryWithHelpers<any, DocType, THelpers, RawDocType, 'deleteOne', TInstanceMethods>;
-    deleteOne(filter: FilterQuery<RawDocType>): QueryWithHelpers<
+    deleteOne(filter: RootFilterQuery<RawDocType>): QueryWithHelpers<
       any,
       DocType,
       THelpers,
@@ -354,7 +357,8 @@ declare module 'mongoose' {
     /** Creates a `distinct` query: returns the distinct values of the given `field` that match `filter`. */
     distinct<DocKey extends string, ResultType = unknown>(
       field: DocKey,
-      filter?: FilterQuery<RawDocType>
+      filter?: RootFilterQuery<RawDocType>,
+      options?: QueryOptions<DocType>
     ): QueryWithHelpers<
       Array<
         DocKey extends keyof WithLevel1NestedPaths<DocType>
@@ -406,52 +410,52 @@ declare module 'mongoose' {
 
     /** Creates a `find` query: gets a list of documents that match `filter`. */
     find(
-      filter: FilterQuery<RawDocType>,
+      filter: RootFilterQuery<RawDocType>,
       projection?: ProjectionType<RawDocType> | null,
       options?: QueryOptions<DocType> | null
     ): QueryWithHelpers<Array<DocType>, DocType, THelpers, RawDocType, 'find', TInstanceMethods>;
     find(
-      filter: FilterQuery<RawDocType>,
+      filter: RootFilterQuery<RawDocType>,
       projection?: ProjectionType<RawDocType> | null
     ): QueryWithHelpers<Array<DocType>, DocType, THelpers, RawDocType, 'find', TInstanceMethods>;
     find(
-      filter: FilterQuery<RawDocType>
+      filter: RootFilterQuery<RawDocType>
     ): QueryWithHelpers<Array<DocType>, DocType, THelpers, RawDocType, 'find', TInstanceMethods>;
     find(): QueryWithHelpers<Array<DocType>, DocType, THelpers, RawDocType, 'find', TInstanceMethods>;
 
     /** Declares the query a findOne operation. When executed, returns the first found document. */
     findOne(
-      filter?: FilterQuery<RawDocType>,
+      filter?: RootFilterQuery<RawDocType>,
       projection?: ProjectionType<RawDocType> | null,
       options?: QueryOptions<DocType> | null
     ): QueryWithHelpers<DocType | null, DocType, THelpers, RawDocType, 'findOne', TInstanceMethods>;
     findOne(
-      filter?: FilterQuery<RawDocType>,
+      filter?: RootFilterQuery<RawDocType>,
       projection?: ProjectionType<RawDocType> | null
     ): QueryWithHelpers<DocType | null, DocType, THelpers, RawDocType, 'findOne', TInstanceMethods>;
     findOne(
-      filter?: FilterQuery<RawDocType>
+      filter?: RootFilterQuery<RawDocType>
     ): QueryWithHelpers<DocType | null, DocType, THelpers, RawDocType, 'findOne', TInstanceMethods>;
 
     /** Creates a `findOneAndDelete` query: atomically finds the given document, deletes it, and returns the document as it was before deletion. */
     findOneAndDelete(
-      filter?: FilterQuery<RawDocType>,
+      filter?: RootFilterQuery<RawDocType>,
       options?: QueryOptions<DocType> | null
     ): QueryWithHelpers<DocType | null, DocType, THelpers, RawDocType, 'findOneAndDelete'>;
 
     /** Creates a `findOneAndUpdate` query: atomically find the first document that matches `filter` and apply `update`. */
     findOneAndUpdate(
-      filter: FilterQuery<RawDocType>,
+      filter: RootFilterQuery<RawDocType>,
       update: UpdateQuery<RawDocType>,
       options: QueryOptions<DocType> & { includeResultMetadata: true }
     ): QueryWithHelpers<ModifyResult<DocType>, DocType, THelpers, RawDocType, 'findOneAndUpdate', TInstanceMethods>;
     findOneAndUpdate(
-      filter: FilterQuery<RawDocType>,
+      filter: RootFilterQuery<RawDocType>,
       update: UpdateQuery<RawDocType>,
       options: QueryOptions<DocType> & { upsert: true } & ReturnsNewDoc
     ): QueryWithHelpers<DocType, DocType, THelpers, RawDocType, 'findOneAndUpdate', TInstanceMethods>;
     findOneAndUpdate(
-      filter?: FilterQuery<RawDocType>,
+      filter?: RootFilterQuery<RawDocType>,
       update?: UpdateQuery<RawDocType>,
       options?: QueryOptions<DocType> | null
     ): QueryWithHelpers<DocType | null, DocType, THelpers, RawDocType, 'findOneAndUpdate', TInstanceMethods>;
@@ -548,9 +552,19 @@ declare module 'mongoose' {
     j(val: boolean | null): this;
 
     /** Sets the lean option. */
-    lean<
-      LeanResultType = GetLeanResultType<RawDocType, ResultType, QueryOp>
-    >(
+    lean(
+      val?: boolean | any
+    ): QueryWithHelpers<
+      ResultType extends null
+        ? GetLeanResultType<RawDocType, ResultType, QueryOp> | null
+        : GetLeanResultType<RawDocType, ResultType, QueryOp>,
+      DocType,
+      THelpers,
+      RawDocType,
+      QueryOp,
+      TInstanceMethods
+      >;
+    lean<LeanResultType>(
       val?: boolean | any
     ): QueryWithHelpers<
       ResultType extends null
@@ -592,7 +606,7 @@ declare module 'mongoose' {
     maxTimeMS(ms: number): this;
 
     /** Merges another Query or conditions object into this one. */
-    merge(source: Query<any, any> | FilterQuery<RawDocType>): this;
+    merge(source: RootFilterQuery<RawDocType>): this;
 
     /** Specifies a `$mod` condition, filters documents for documents whose `path` property is a number that is equal to `remainder` modulo `divisor`. */
     mod<K = string>(path: K, val: number): this;
@@ -711,7 +725,7 @@ declare module 'mongoose' {
      * not accept any [atomic](https://www.mongodb.com/docs/manual/tutorial/model-data-for-atomic-operations/#pattern) operators (`$set`, etc.)
      */
     replaceOne(
-      filter?: FilterQuery<RawDocType>,
+      filter?: RootFilterQuery<RawDocType>,
       replacement?: DocType | AnyObject,
       options?: QueryOptions<DocType> | null
     ): QueryWithHelpers<any, DocType, THelpers, RawDocType, 'replaceOne', TInstanceMethods>;
@@ -819,7 +833,7 @@ declare module 'mongoose' {
      * the `multi` option.
      */
     updateMany(
-      filter?: FilterQuery<RawDocType>,
+      filter?: RootFilterQuery<RawDocType>,
       update?: UpdateQuery<RawDocType> | UpdateWithAggregationPipeline,
       options?: QueryOptions<DocType> | null
     ): QueryWithHelpers<UpdateWriteOpResult, DocType, THelpers, RawDocType, 'updateMany', TInstanceMethods>;
@@ -829,7 +843,7 @@ declare module 'mongoose' {
      * `update()`, except it does not support the `multi` or `overwrite` options.
      */
     updateOne(
-      filter?: FilterQuery<RawDocType>,
+      filter?: RootFilterQuery<RawDocType>,
       update?: UpdateQuery<RawDocType> | UpdateWithAggregationPipeline,
       options?: QueryOptions<DocType> | null
     ): QueryWithHelpers<UpdateWriteOpResult, DocType, THelpers, RawDocType, 'updateOne', TInstanceMethods>;