For notes, I use a text editor and Resilio Sync/Syncthing. It's great!
Can you please describe this setup ?
Did I mention? The devices don't even need to be connected to the internet! They only need to be on the same LAN!
I have other synced folders, including PDFs, music and phone pictures/videos.
My girlfriend and I have a Resilio Sync folder that we use to share stuff with each other. It works flawlessly and we don't even need the internet!
Resilio Sync and Syncthing are amazing tools. If you have any capacity to fix bugs, I recommend using Syncthing (open source), so that you can potentially fix bugs :) It's becoming much more stable, but could always use the support!