Will not take Startup or Apple password on new system Tahoe 26.0.1

Since switching to the newest system on my iMac M1 — when I shutdown the computer and/or restart — it will not take my current, or previous passwords. Only when I mess with it several times using another "Test" person, does it eventually let me on.

Since I've tried the only two passwords I've used, and am still locked out. How do I get in to change the password to let me on each morning?