How to recover old username after profile gets reset?

Title. My profile (display name, username, profile picture, bio) got reset because I included something sensitive in my about me. Since it only lasted 24h I naturally wanted to get my old username back, but when I try to, it says I can’t update the username because it’s what, “taken”? By nobody else but… me???

It’s been literally a week since I received the warning, and my own profile even used to appear in the search box when I searched for my old username, but I somehow still can’t get it back.

Is there any way to recover it? I already tried contacting support, but they didn’t provide me with a solution that worked.