Wouldn’t that be nice!
The only thing I could think of is that I imagine a plugin exists (or could reasonably easily be created) that lets a single note appear to exist as two separate notes. It wouldn’t meet your request for the syncing of just a paragraph.
Perhaps once you started composing separate unique paragraphs it would have to be done in some sort of transitory interstitial dialog akin to the hover plugin. And this would perhaps keep the other unedited note as a deep copy of the current state of the edited note but hide the differences. Honestly, I obviously don’t have the know-how to even properly explain what I am getting at, but the basic premise to make it doable would be the occasional flushing of the hidden bits with the matching content already identified and quickly instanced in both. Like, the idea would be to save the memory until a region was clicked into and actually edited the first time.
I probably should just delete this post because it may do more harm than good. With your skills, f you are asking this question, I doubt my amateur riffs are going to trigger any sparks. But, it’s always worth trying. I would surely love the feature very very much. This request I made a while back is in a similar ballpark: Append independent quasi-editable embeds without propagation to source
Good luck! Thanks for making this post!