I think the multiple communities of the same topic across different instances is a mistake honestly. Information/discussion should be concentrated, not spread about a bunch of places.
I read on here they are working on a method that would allow communities across instances to merge. I hope that happens.
Imo, federation should mean the same communities are replicated across all instances. If an instance wants to house its own content, they can maybe make a community that isn’t replicated to all the others but accessible nonetheless by everyone (ie Piracy community, maybe not every instance owner wants to replicate that to their instance).
I dunno, the bifurcation of communities just seems like a mistake and less efficient than everyone in the same place sharing knowledge and ideas.