How to access locked notes if you don’t remember your password

From: How to lock or unlock notes on your iPhone or iPad - Apple Support

"If you use a unique password for Notes, there is no way to access your locked notes if you forget the password. "

Resetting the password doesn’t change it for the notes already locked. It merely changes it so you can save and open new notes going forward.

There is no way to reset the password on an already locked note. You must remember the password or you cannot open the note.