Change forum Username

Trying to find out if/how to change my username. Changing the email address and my name is easily done, but not so much when it comes to the username.

try this one:
Снимок экрана 2021-05-29 в 19.06.10

then do this:

For some reason, my interface at that spot doesn’t have a “pencil” (edit) icon there. I am able to change my “name”, “email”, and photo but it will not allow me the option to change my username…

Maybe it has to do with my community “level”…