Can't create user???

I had to grab some Macbook Pro’s from the office to refurbish for new hires. I wiped one out and reinstalled the Mac OS. It was Catalina at the time. I created a new user upon the first boot like normal and then I upgraded it to Big Sur.

Now I need to create a new local admin account for the user so I head to System Preferences > Users & Groups, click the lock symbol to make changes and for some reason, it won’t accept my password. I restarted and logged in with my password, repeated the steps, and the same thing. I even changed

my password but it wouldn’t accept it to create another user. My account shows

it’s the only one on there and it is an admin account.

I’m stumped…