I think it should be like joining a mining pool, if you create a server you don’t have admin privileges like they exist here at the moment, you’re added to the pool of machines that stores info and users don’t choose a server at all, the servers communicate between themselves to make sure all info is backed up on at least three machines.
From the front end it looks like any equivalent private social media, one website for everything. On the back end side the servers are all over the place instead of in a couple data centers.
Server owners could decide to ban certain communities from storing info on their server, but that wouldn’t delete the community, it would just rely on being hosted elsewhere (hence the triple backup at all times) and users would be responsible for curating their own feed.
It would solve the issue of having to switch server if you disagree with the admin’s decision and would make the experience much more user friendly. Each new server would improve the stability of the whole network by taking part of the load and making sure that if one server is down, others have the same content available so no user can tell that there’s something wrong happening behind the scene.