I would like to change my username to something of my choice.

How would I do that?

There really needs to be a pinned thread of people who wanna change their usernames
Maybe have a limit of one change per 3 months

We're not changing usernames for the same reason we're not deleting accounts anymore.

Fair

And what would be that reason? If I can't change it I would've asked to delete it. I really don't want to be here anymore for personal reasons. I would very much appreciate it if you helped me.

Just stop using your account. Nobody is forcing you to log in and changing your name wouldn't do anything to stop you from logging in with the new name either. I'm locking this thread now.