And also the fact that the shape of data sent and understood by servers varies and you can't use any intuitive reasoning at all because there are multiple ways to express the same thing in AP.
You can see how this approach worked for Discord. IME forums and threads were rarely used, and forum channels ended up being more like extra chat channels. Tumblr added communities and most activity still occurs outside of them.
You have to bake these things into the usage pattern right from the start and design them in a way so they won't be "circumvented" by lower-effort (in terms of usage) features.