I time travel with unciv. This is how I once survived a 15 hour long haul flight.

I’ve been looking up a solution myself for years. I ended up with encrypting my note folder with Gocryptfs and synchronize the folder with Syncthing.
Requires quite the setup at first, but perfectly fits my needs (I also use extensively the terminal).
On android there is DroidFS to decrypt your synched folder and read the notes in mobile, but I couldn’t find a way to edit them.