So it sounds like you’re wanting these two things:
List-specific song preferences
I think this will be a bit of a technical challenge, but enough folks have been asking about it that I am going to at least give it my best shot when I get a chance. Most likely it will be an opt-in setting that you can turn on for a particular list, so that the behavior doesn’t change for folks who want it to behave the way it does now.
Song-specific instrument preferences
This will be part of the big strumming patterns update that will be coming out in the first few months of 2022.