Mac Mini login: Forgot user ID/password

I have a used Mac Mini M1 that will not go through a boot cycle. The led status light flashes yellow shortly after starting and that's as far as it will go. Troubleshooting online says that it needs to have its firmware updated. However in researching THAT, it can only be done with another Apple Silicon computer! So, I've gotten another one, and it worked just fine, but a couple of months have passed while I did the research and have finally gotten back to it. Now I have a problem with the USER ID and PW on the 2nd one that boots. I normally wouldn't have established a UID/PW for a computer I hadn't yet set up for my personal use, but apparently I did, because it won't continue the boot up without it. I put in every single combination I have ever used for a simple UID/PW that isn't going to be vital to protect data that isn't on the computer yet. There are only 3 or 4 that I would use so I don't have to remember so many needlessly. However since I need to have BOTH the UID AND the PW correct, I can't seem to get anything that works. I'm locked out and have to wait 5 minutes in between guesses. I've already been through all the guesses that I might have used including the "user ID" / "password" that some computer refurbishers use. Is there a way to get back in to my locked computer? Doing a complete reload is fine since I have yet to put any files on the HDD/SSD.