Even with a star topology, how do you go about preserving user intent for text insertions without CRDTs and without rewriting (transforming) mutations so that client and server result in same state (basically OT)?

When inserting text, you can either use mutations that insert the text relative to some reference character(s) or at some index. The former is basically the approach of most text CRDTs. I'm having a hard time imagining the latter without modifying the insertion index relative to concurrent insertions or deletions. I believe that Jupiter based OT imposes a global order, but uses it to determine how concurrent mutations are transformed against one another.