M3 MacPro 2023 Owner User deleted

OK, I've boobed. I have a functioning system, i.e. I can work with my three standard user accounts and have an admin account BUT it is not the owner User Admin. So, I have a Time Machine bckup drive with plenty of backups (and the latest with the Owner User missing but some earlier ones with it present. Currently the Admin User I have cannot set a backup going ('You do not have permmission'). the permission cannot be changed.

I'm looking for some ways (if there are a few then the easiest or less risky first) to restore the original Owner User Admin without loosing the other Users. Or if a reset to factory has to be done be 100% confident that the backups I have and the time machine will allow me to restore all the three users.

Latest Sequoia running.