Recover an overwritten Mac note
Even if you’re sure you don’t use iCloud, go ahead and turn it on and check https://iCloud.com for notes and deleted notes.
Even if you’re sure you don’t use time machine, connect a drive and see if you can enter time machine to browse local backups and snapshots.
These two methods have saved me and also saved people that were convinced they didn’t have backups.
I hope you have a backup of some sort to piece together the notes database and don’t lose this work.