You can run your own server if you want to, or join one that has the same level of moderation as you'd like. As for defederation that's just freedom of association

I'm not sure I would describe them as "barely-working". Have you used any of them lately? They work very well in my experience.

The improvement I think is you can jump to a different instance, and being all your followers and following with you. Whereas if you're the subject of an arbitrary decision by the Twitter overlord, all you can really do is post about it online and try to stir up enough bad PR for the company that they reverse their decision.