I believe that you are close to the mark the market is starting to look for.
I hope to build a competitive system as I think I know how to bring it together with a workable business model. When I have the time...
It exists for 5 years already: https://communick.com
Given Apple's moves in the iOS app space and the way young people talk and behave; the next social media platform will be a low paid app that has full privacy and is non-ad revenue based and is centralized.
It will be some company that is super transparent but at the same time has figured out that one can provide paid services of value user of social media would pay for.
It might even be one of us that is reading this message that goes on to form such a social platform.