Used this script and https://writeapp.net/notesexporter/ to export text from notes.app

gistfile1.txt

import os
from markdownify import markdownify as md

import sys
print(sys.getdefaultencoding())

NOTES_PATH = "/Users/f00/Documents/notes-backup"
notes = os.listdir(NOTES_PATH)

for note in notes:
    with open(f"{NOTES_PATH}/{note}", 'r+', encoding="ISO-8859-1") as f:
        note_data = f.read()
        f.write(md(note_data))

for note in notes:
    os.rename(f"{NOTES_PATH}/{note}", f"{NOTES_PATH}/{note[len('Notes'):].replace('.txt', '.md')}")