Meh. Username shouldn’t matter anyway. Make sure the password is secure (and stored securely).
I had a loaned ISP router in the early naughts that I couldn’t change the admin password, but it was the same for all their boxes and someone posted it on my bulletin board. I changed it as soon as I could, but the techs were furious. Whatever man, I’m not letting anyone take control of my LAN because you can’t figure this shit out.