@OP why not register the Username that you want if your problem is the limitation you can buy the
Copper membership to increase the limitation it is cheaper around 40k sats.
Perhaps this is probably the best idea OP can get. I thought of it too, instead of struggle too much for an account that you're probably going forgo some day and just focus on creating a new one and surely @OP can afford copper member for lifting the limitations.
OP consider BitMaxz suggestion it's probably the best knowledge or idea you can get towards your want or least keep waiting for admins responses which is under probability if they would accept the proposal even if they get to see it.