Yes, Mastodon is confusing because it's so diversified. You pick a server, choosing whom to trust as administrator. You can still follow people on other instances, though. "It's like email, pick a server but talk to everybody," as they are prone to explain. There's also Counter.Social, which used to be a Mastodon instance before becoming its own thing, no longer part of the Mastodon federation. It's actually a much-simplified user experience because it's a single service, which you might enjoy. I'm also on MeWe, which is fine but has its own strong conservative presence there.