That's an interesting idea.
A "bring your own cloud" provider could be used for DocNode Sync. For example, Dropbox. Dropbox doesn't have the ability to resolve conflicts, but it can be used to deterministically store the order of operations. Then, clients would reconcile and combine the operations into a single state file. Authentication might be a bit tricky, since permissions would have to reside elsewhere. But I think it's doable.
I'll consider it!
I think I do want to solve conflicts. My use case is for a personal database, which simplifies things a bit: sync is between devices of a single person, so it's unlikely for concurrent offline changes to occur.
What I have in mind is a setup like the one from this experiment: https://tonsky.me/blog/crdt-filesync/ . I don't know if it's at all possible in my use case though, or–in case it is possible–if it ends up being practical. As you said, the resulting user experience might be so strange that it's not something users want.
Anyway, thanks again for the info and good luck with DocNode. :)