Honestly Apple Notes works really well. It doesn't have much features, but its simplicity should be the baseline of any note taking app
Notes satisfies my three must-have requirements: it’s on every device my wife and I use, it allows mixing checklists with free form text, and we can effortlessly share information with each other.
I just checked and found that I have 1,321 total notes stored in iCloud. These range from my daily todo lists (invaluable for end of year performance review documents, saying nothing of just remembering what I’m supposed to do), to the all-important shared grocery list, which we will both update whenever we’re shopping at the grocery store.
I literally went to the apple notes discord once and asked them directly and their response was basically "Apple Notes isn't design to be used for more than 100 notes"... so be very very careful about choosing to use Apple Notes cause you may never get your notes out of there
Anyways, if you have access to a Mac you can sync your notes via iCloud and then on Mac you can easily access the SQLite DB containing the notes. If you can figure out the schema it would be easy to write a tool to export this automatically. I’d guess someone has already built such a tool.
That said, it *absolutely boggles my mind that there is no Markdown support*.