Node groups does not work in Blender 3.5

[Durman]

Problem statement

Node Group Sockets
Virtual sockets are the extra sockets added to group input and output nodes. Previously connecting a link to them would create an input or output in the corresponding node group. That feature was meant as a UI/UX feature though, and is now implemented differently in Blender and doesn't happen automatically. The correct way to add a group input from Python is to use node_tree.inputs.new(...) (70260960994d).

That is not only problem. Another is that group nodes does not generate sockets according to changes in inputs/outputs of their sub trees. Whether it's a bug or not is not clear yet - https://projects.blender.org/blender/blender/issues/105283

One more problem - https://projects.blender.org/blender/blender/issues/109231