I am syncing between two laptops, a phone, a tablet and nvidia shield (not for Joplin on the shield lol, just files). The only issue with Syncthing is that it sometimes gets battery optimized by Samsung despite everything I have tried to get it to stay foregrounded. But as soon as I open Syncthing it syncs instantly since markdown files are so small. Then Joplin can pull from the local files. I have it set to be encrypted so it takes a little longer to import than it would otherwise. For Joplin, now that it has automatic system dark mode it is almost perfect. The only thing I'd prefer was a better tablet UI with a paned view. Other than that I am content! They also have OCR in the betas, which gets it a little closer to being an Evernote premium replacement. It is impressive what they've added despite being a nonprofit open-source project made by volunteers