I tried SimpleX but the VPN kill switch on my phone prevents syncing with my computer.
I use telegram primarily as a note taking app with sync features.
Occasionally I send files to friends, so having easy set up for tech illiterate would be great.
There are lots of options. Why are you using a chat app for note taking?
Couldn’t you just get a markdown note app that syncs with something like syncthing?
I don’t know their exact use case, but I use it a lot to save links. They can be saved very quick to the saved messages “chat”.
However, recently I got a new phone and now the Matrix client is also opening quickly, instead of taking 10+ seconds, so I’ll switch to sending them to a private room with me being the only participant.
But! I think Markor (from F-droid) also allows sharing arbitrary text to a file, so that could work too. A chat app may be better, though, because it records exact timestamps, and always records linksas a distinct message, so it may be more suitable for your own automated processing later.