There are certainly opportunities for improvement of the UX of moving servers, and that would be great to do
And yes there is a fundamental limit to what can be done because the architecture of ActivityPub bundles everything (including identity, moderation, and content) into a single architectural component, the instance
I'd love to see ActivityPub in general, or just Mastodon in particular, moving towards a more unbundled model similar to ATProto (BluSky)