Ah! Backups have always been by worry. What simple app are you using for the "save as TXT" backups?
EDIT: I just tried running it, and nothing happened. Might be a beta macOS Monterrey problem.
EDIT 2: this just worked for me, needs an iPad, but copies Notes as markdown files that then also show up on my Mac: https://wimpostma.com/blog/how-to-export-and-backup-notes-fr...