I would suggest going all-in on SQLite and even encrypting it on disk: https://sqlite.org/com/see.html https://sqlite.org/com/see.html An encrypted DB will be

I would suggest going all-in on SQLite and even encrypting it on disk: https://sqlite.org/com/see.html https://sqlite.org/com/see.html An encrypted DB will be a differentiator compared to every other offline editor (Joplin et al). It would also appeal to privacy-conscious enterprise users whose laptops may get automatically backed up. You can support a timed export to text files for those other use-cases.