People over complicate federation. I write federated software so lemme break it down. Federation just means data sharing. When you post something on a federation enabled website it sends a copy of your post to everyone who follows you and tells their service to store your data in their database in addition to their own data. What this means is that you can’t just blow up a server to shut it down because everyone in the game has a copy.
This is my biggest fear. The hidden weakness of the fediverse is that the largest implementation gets to set the rules of federation