If the descentralization of social networks continue, we will have to prepare for the eventual rise of the instances wars, where people will start to fight about which instance is better and which one is weird to be in and so on, but that’s for the future of us all.
No, you can see all the content from all instances you’re subscribed to, as long your instance admin hasn’t defederated from them.
Right, I think this was the potential concern I was vaguely remembering.