Cannot find old Notes data
If you didn't use iCloud, the notes are stored in:
~/Library/Group Containers/group.com.apple.notes/ in a database file named NoteStore.sqlite
If you used iCloud, your notes are stored at:
~/Library/Containers/com.apple.Notes/Data/CloudKit/
To view the Notes you need an SQL app or typing sqlite at the command line.

https://github.com/jakwings/mac-notes-exporter