Can you edit your username?
Please contact email@example.com to see if your username can be edited.
I have been under the impression that this answer is always no.
I once asked an Esri admin, and this was their answer to me:
There is not a way to change your username. It’s linked to your Esri Account. You can create a new account and have this one deactivated, but your points and activity wouldn’t be transferred over.
Retrieving data ...