I thought I was going to get through life without having to wrestle with Notes, then about 14 years ago I had a gig where the client was still using it. Sigh!
So I had an app ON MY DESKTOP called KillNotes. When Notes would crash, I could run KillNotes to shut down all the background cruft left behind, and then I could restart Notes. If I didn’t have KillNotes, I had to reboot the machine to get Notes going again. LOL!
Notes is supposedly finally going away in a few months.
There is no support for the current version.
Other than a couple of tweaks and restarting the notes box, I’m out of ideas.