With respect, syncthing is a PITA an no average person is ever going to use that, imo. The average user thinks, “what can solve this problem.” They don’t think, “what set of different apps can I use to work together to partially solve this problem in an iffy and unreliable way?”

As someone who has spent years doing the latter with SO many different tools, I despise how annoying and unreliable it all is. No chance it ever becomes broadly used by others.