rework "use existing cognito resources" prose, highlight configuring client libs directly

src/pages/[platform]/build-a-backend/auth/use-existing-cognito-resources/index.mdx

@@ -29,21 +29,96 @@ export function getStaticProps(context) {
   };
 }
 
-Amplify Auth can be configured to use an existing Amazon Cognito user pool and identity pool. If you are in a team setting or part of a company that has previously created auth resources, you have a few different options to configure your application to use existing auth resources.
+Amplify Auth can be configured to use an existing Amazon Cognito user pool and identity pool. If you are in a team setting or part of a company that has previously created auth resources, you can [configure the client library directly](#use-auth-resources-without-an-amplify-backend), or maintain references with [AWS Cloud Development Kit (AWS CDK)](https://aws.amazon.com/cdk/) in your Amplify backend.
 
-If you are using Amplify to build your backend, it is recommended to [add a reference to your auth resource using `backend.addOutput`](#use-auth-resources-with-an-amplify-backend).
+<Callout info>
+
+**Note:** when using existing auth resources, it may be necessary to add additional policies or permissions for your authenticated and unauthenticated IAM roles. These changes must be performed manually.
+
+</Callout>
+
+## Use auth resources without an Amplify backend
+
+<InlineFilter filters={["angular", "javascript", "nextjs", "react", "react-native", "vue"]}>
+
+You can use existing resources without an Amplify backend by configuring the client library directly.
+
+```ts title="src/main.ts"
+import { Amplify } from "aws-amplify"
+
+Amplify.configure({
+  Auth: {
+    Cognito: {
+      userPoolId: "<your-cognito-user-pool-id>",
+      userPoolClientId: "<your-cognito-user-pool-client-id>",
+      identityPoolId: "<your-cognito-identity-pool-id>",
+      loginWith: {
+        email: true,
+      },
+      signUpVerificationMethod: "code",
+      userAttributes: {
+        email: {
+          required: true,
+        },
+      },
+      allowGuestAccess: true,
+      passwordFormat: {
+        minLength: 8,
+        requireLowercase: true,
+        requireUppercase: true,
+        requireNumbers: true,
+        requireSpecialCharacters: true,
+      },
+    },
+  },
+})
+```
+
+</InlineFilter>
+<InlineFilter filters={["android", "flutter", "swift"]}>
 
-If you do not use Amplify to build your backend, you can [configure the client library directly](#use-auth-resources-without-an-amplify-backend).
+Configuring the mobile client libraries directly is not supported, however you can manually create `amplify_outputs.json` with the following schema:
 
 <Callout info>
 
-**Note:** when using existing auth resources, it may be necessary to add policies or permissions for your authenticated and unauthenticated IAM roles. These changes must be performed manually using the [AWS Cloud Development Kit (AWS CDK)](https://aws.amazon.com/cdk/)
+**Note:** it is strongly recommended to use backend outputs to generate this file for each sandbox or branch deployment
 
 </Callout>
 
+```json title="amplify_outputs.json"
+{
+  "version": "1",
+  "auth": {
+    "aws_region": "<your-cognito-aws-region>",
+    "user_pool_id": "<your-cognito-user-pool-id>",
+    "user_pool_client_id": "<your-cognito-user-pool-client-id>",
+    "identity_pool_id": "<your-cognito-identity-pool-id>",
+    "username_attributes": ["email"],
+    "standard_required_attributes": ["email"],
+    "user_verification_types": ["email"],
+    "unauthenticated_identities_enabled": true,
+    "password_policy": {
+      "min_length": 8,
+      "require_lowercase": true,
+      "require_uppercase": true,
+      "require_numbers": true,
+      "require_symbols": true
+    }
+  }
+}
+```
+
+</InlineFilter>
+
 ## Use auth resources with an Amplify backend
 
-The easiest way to get started with your existing resource is to use `backend.addOutput` to surface auth configuration to `amplify_outputs.json` automatically. In it's simplest form:
+<Callout warning>
+
+**Warning:** Amplify resources do not support including auth configurations by referencing with CDK. We are currently working to improve this experience by providing first-class support for referencing existing auth resources. [View the RFC for `referenceAuth` for more details](https://github.com/aws-amplify/amplify-backend/issues/1548)
+
+</Callout>
+
+To get started with your existing resource in your frontend application, to use `backend.addOutput` to surface auth configuration to `amplify_outputs.json` automatically. In it's simplest form:
 
 ```ts title="amplify/backend.ts"
 import { defineBackend } from "@aws-amplify/backend"
@@ -130,80 +205,6 @@ backend.addOutput({
 })
 ```
 
-## Use auth resources without an Amplify backend
-
-Alternatively, you can use existing resources without an Amplify backend.
-
-<InlineFilter filters={["angular", "javascript", "nextjs", "react", "react-native", "vue"]}>
-
-```ts title="src/main.ts"
-import { Amplify } from "aws-amplify"
-
-Amplify.configure({
-  Auth: {
-    Cognito: {
-      userPoolId: "<your-cognito-user-pool-id>",
-      userPoolClientId: "<your-cognito-user-pool-client-id>",
-      identityPoolId: "<your-cognito-identity-pool-id>",
-      loginWith: {
-        email: true,
-      },
-      signUpVerificationMethod: "code",
-      userAttributes: {
-        email: {
-          required: true,
-        },
-      },
-      allowGuestAccess: true,
-      passwordFormat: {
-        minLength: 8,
-        requireLowercase: true,
-        requireUppercase: true,
-        requireNumbers: true,
-        requireSpecialCharacters: true,
-      },
-    },
-  },
-})
-```
-
-</InlineFilter>
-<InlineFilter filters={["android", "flutter", "swift"]}>
-
-Configuring the mobile client libraries directly is not supported, however you can manually create `amplify_outputs.json` with the following schema:
-
-<Callout info>
-
-**Note:** it is strongly recommended to use backend outputs to generate this file for each sandbox or branch deployment
-
-</Callout>
-
-{/* pending hosted outputs schema */}
-```json title="amplify_outputs.json"
-{
-  "version": "1",
-  "auth": {
-    "aws_region": "<your-cognito-aws-region>",
-    "user_pool_id": "<your-cognito-user-pool-id>",
-    "user_pool_client_id": "<your-cognito-user-pool-client-id>",
-    "identity_pool_id": "<your-cognito-identity-pool-id>",
-    "username_attributes": ["email"],
-    "standard_required_attributes": ["email"],
-    "user_verification_types": ["email"],
-    "unauthenticated_identities_enabled": true,
-    "password_policy": {
-      "min_length": 8,
-      "require_lowercase": true,
-      "require_uppercase": true,
-      "require_numbers": true,
-      "require_symbols": true
-    }
-  }
-}
-```
-
-</InlineFilter>
-
 ## Next steps
 
 - [Learn how to connect your frontend](/[platform]/build-a-backend/auth/connect-your-frontend/)