Well, the approach I use is “synology Drive” and I replicate it down to all clients. Also, NAS 6 with regular offline backups on the server.

Lacking an equivalent, there are multiple peer to peer replication tools. I used one to replicate Balder’s Gate III saves between gaming laptops.

If you decide to build something, plz try to make it a pluggable feature to existing clients rather than fork one or more implementations.