Sorry I haven’t been following along and I have only a fuzzy idea of how these Twitter competitors work. Do users and posts on pixelfed federate with Bsky?

I’ve heard of some people I know leaving Twitter for bsky. I never used Twitter myself. So if I want to suddenly become social do I have to join bsky to follow them etc or is there a whole constellation of alternatives?

And if there are alternatives, which servers do the programmers who don’t want politics and memes and stuff congregate on?