I'm pretty sure it's not possible. But you can remove your current account and create a new one though

Delete your account and re-register. You can also have a display name, but your username will still show on other instance's posts.

Yeah but I just spent a good 30 minutes importing all of my current Apollo subreddits via wefwef. Lost cause?

Thanks! It looks like replying in wefwef and Memmy is still a work in progress…

Consider every account a burner, they don't matter and don't form your identity