I am pretty sure that every data they ever gathered about you is still there, just marked as hidden. Data is their currency; you don’t throw that away.

How about starting your own sub - here or on Reddit? Then you are the mod.

I think, the “threadiverse” is more akin to the old (also federated, just in a different way) Usenet / Newsgroups than web-forums. So “ScoopGroups”, maybe?

Mastodon or Pixelfed come to mind.