There are some open source tools, e.g. https://github.com/storizzi/notes-exporter https://github.com/storizzi/notes-exporter I've used another tool in the past

There are some open source tools, e.g. https://github.com/storizzi/notes-exporter https://github.com/storizzi/notes-exporter I've used another tool in the past (cannot remember the name), and it worked ok. I personally cannot trust Apple to store data, so I only use Apple Notes for throw-away notes like shopping lists.