When I was taking notes in Mac with iCloud (default AppleID) account, everytime I used to edit a notes, a duplicate used to get created. This has made me the notes feature completely unusable with cloud-storage.
Then I have enabled google account and all the notes were stored in google notes. When my MacBookPro (SSD) crashed a few weeks ago, I googled a lot to retrieve my notes that were being stored in google account. However, to my surprise, notes.google.com is completely a different product and my notes were not found there. I even searched my google-drive but I still did not find the notes.
Had my mac was not crashed, even then I found that there is no easy way of exporting all the notes in one shot. Backing up notes one-by-one from apple-notes is a nightmare.