You know what, why don’t you just write a superior syncthing without unnecessary, weirdly complicated things where no complexity is necessary, in Java? Why are you even going on about all this when it’s so trivial to do it simply and clearly in your language of choice?
I’m a big believer in public information distribution, so please don’t put words in my mouth. However I don’t see why this isn’t perfectly covered by existing technologies - BitTorrent as one example, or for that matter HTTP(S)… Regarding the state machine implementation or whatever, see above.