What is the username of the macOS recovery? so I am trying to add a user to the admin group on my computer, but I don't have any admin powers. I do however, know the password that allows me to enter the macOS recovery mode, which I think must be in the admin group and I could use to give another user admin powers.

Does anyone know the username of this macOS recovery account?
macOS recovery doesn't really have users or passwords. Well, technically it does have one user account: root. But Recovery's root account doesn't have a password; when you start in Recovery mode you're automatically logged in as root.

If you need to enter a password to get into Recovery mode, that's probably a firmware password. If a firmware password is set, you need to enter it in order to invoke any alternate boot mode (such as Recovery). This password has nothing to do with any user name or account, and has no use after the computer has started up.