[phyrex]

I don't want another social network or collaboration platform, I just wants something that synchronizes files across machines :/

[toomuchtodo]

iCloud Files, OneDrive, Google Drive, SyncThing

SyncThing, being solid and open source (and not beholden to commercial interests) would be my suggestion.

[wodenokoto]

I don’t know syncthing, but the other 3 I’m pretty sure are collaboration platforms too.