Sometimes I fold contents under a specific heading or a specific item of list. When I reopen this note next time, I want the system remember which one I have folded / unfolded.
Proposed solution
Put a code in/under the specific heading or list, make it invisible in preview mode, and use it to dedicate the state of folding/unfolding.
Since no one has yet said that this is not going to happen, I think it is a feature request worth keeping open. Personally, I think that this would be really nice as a core feature.