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.
Sorry for a bit of off-topic, but for a note taking app I suggest checking out Amplenote (there is a free plan for browser and mobile apps). I discovered it recently and it’s quite a life changer for me. Proper tag system for notes is a killer feature.