YJS (and Kevin Jahns!) is fantastic, although I'm not sure they're interested in addressing all of these problems. In so far YJS has been very focused on replicating state from one place to another.
And the parent comment may be making light of some of the big issues in the space. You need to be generic, but also performant and simple compared to the competition.
Real time text editing is not trivial although there's solid prior art now. Even undo management is a whole problem space (what should a cross user undo look like if there have been dependent changes).
Yjs is exactly that. It is a simple abstraction for building any kind of collaborative application. It has ready to use solutions for most problems related to this problem space. The selective UndoManager, for example, is generic&configurable and can be reused for all kinds of stuff. It supports many different editors. It supports many different (scalable) backends.
It is much more than state synchronization.
If there is anything missing, then let's work on it. Yjs is extensible and allows for custom features that others can reuse.
Fluid Framework (a project I contribute to/work on through Microsoft) supports this via token in our default service implementation, but we don't have integration with an ACL DB.
And the parent comment may be making light of some of the big issues in the space. You need to be generic, but also performant and simple compared to the competition.
Real time text editing is not trivial although there's solid prior art now. Even undo management is a whole problem space (what should a cross user undo look like if there have been dependent changes).