Not to dismiss your argument/stack preference, but forgoing the front end for a graphic design tool might prove difficult. EDIT: But yes, CRDT-backed stores are definitely the way to go for a requirement like this.
> but forgoing the front end for a graphic design tool might prove difficult
How so?
Offline support? Collaborative tools don't really have a good offline story by nature.
Ping times? If you use fly.io you're going to have great availability and low latency. It's like a CDN for live apps.
I'm not biased against a 'client-side front end', it's just that a collaborative tool that is 'always online' might as well use a 'live app' style where the server drives the DOM. It solves all the problems that the OP raised in the quote, and it's less about where React should go next, because client-side front end literally can't solve those problems due to their nature.
Not to dismiss your argument/stack preference, but forgoing the front end for a graphic design tool might prove difficult. EDIT: But yes, CRDT-backed stores are definitely the way to go for a requirement like this.