Probably simplest solution is to keep current behaviour and get a second iPad for notes.
This reminds me of a response from a Microsoft MVP on a question about reducing storage usage by stale installer files in Windows folder:
"Essentially to reduce the space used you need to increase the size lf your storage"
This must have been why they had so many extra PADDs in Star Trek. The only real way to multi-task!
Any self-respecting Apple user has at least three iPads.