#OP
As you possess knowledge of neither the email address nor the password, only the username, it is quite unlikely you will reacquire access to your account.
Actually the same for me, I have maybe a possibility of email but not sure and I have something that could be a proof but I would also Want to change the username of the acc
you cannot change username nor can you restore without access to e-mail it was created with.
Time to let it go.