This was the main reason I started my own Mastodon server, because I couldn't change my username when I went to give Mastodon another try after Musk bought Twitter.
I guess it worked out in the end, I'm glad I have that experience, and the freedom. Still, definitely a great feature to have available.
@stefan @loops Yeah this is something we're working on in Pixelfed too!
It's a bit more tricky with PF because object ids contain the username, but with Loops we can launch with this support!