That’s not necessarily true; if you use Origin Private Filesystem along with a Web Worker that acts as a local database server and works off a single SQLite dat

That’s not necessarily true; if you use Origin Private Filesystem along with a Web Worker that acts as a local database server and works off a single SQLite database, you at least have a single DB file per device. From there on, your problem becomes state reconciliation on the server, which CRDTs should help solving. Not an easy problem for sure, but the web platform is surprisingly capable these days.