Backup iCloud notes?
There is an app called Exporter that will export each note in Notes to a markdown or html file to any folder you choose. So you could save these to an external drive or another internal drive. Its not blazing fast. i just saved 700 files in about 1.5 minutes. So figure 15 minutes to save 7000 files. Exporter is free from App Store. Go to Exporter/Preferences to change output files from Markdown to HTML if thats the format you want.