Can you edit your username?
Please contact firstname.lastname@example.org 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.
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