At https://support.apple.com/en-us/HT204055, Apple provides instructions for a bunch of stuff you might want to export:

  • iCloud Drive files
  • Photos and videos
  • Mail
  • Contacts
  • Calendar
  • Reminders
  • Safari
  • Notes
  • Voice Memos

And/or you can use https://privacy.apple.com/, which is basically Apple's version of Google Takeout.

These are a joke of instructions, per-note app-only export to an awful pdf format