You have to enter the ACTUAL Password you used when you password locked the notes. Face ID has never been a replacement for Passcodes/Passwords. It is a convenience which works in tandem with Passcodes/Passwords.
If you didn't write this important password down when you created it, nor create a password hint when you were given the opportunity to, the notes will remain locked forever until you enter the right password. There is NO workaround. The password is encrypted directly on the device. Apple can't help you. Only you can get access to the notes with the correct password.
It is really important to note important passcodes and passwords somewhere for future recall. Something as old fashioned and simple as this can save you in the future: