

Polyproto is a really exciting one I’m keeping an eye on, though it’s still very early in development. It’s a protocol that allows for migrating accounts like you mentioned since the user owns their own identity. AFAIK only a chat app is being worked on right now, but the protocol allows for extensions and I don’t see any reason it wouldn’t work for other social media
If you want to donate to lemmy instances (or the devs as well if the other replies haven’t changed your mind) a lot of them are on Liberapay and if yours isn’t, they probably have a donate link on their web UI.