If you store notes on disk, which is what I do, you can back them up with any file backup tool.

I store my notes (encrypted with a password) on OneDrive.

See https://edna.arslexis.io/help-win#storing-notes-on-disk

I even have a settings option for a daily backup which exports all notes into a single .zip file in `backups` sub-directory. Not sure if it makes much sense, but it's there.