Well said. This almost perfectly describes my experience with Mastodon as well. I ended up joining a Firefish instance later which was better, but no amount of "antennas" or topic follows helps when your instance has 20 users and it can't find anything.

I'd imagine a platform supposedly started by the people who founded Twitter, built from what supposedly was once an internal test of modifications to Twitter, to have an easier onboarding experience than whatever Mastodon did back when I tried it.

Bluesky works almost exactly like Twitter right now. It makes a vague mention of federation on signup but it's basically irrelevant and everything right now still goes through their central server, so there is no issue finding content or users.