I am also interested in the same. For the time being, I am experimenting with the solution posted here: 📖 How to typeset two texts in parallel on pairs of facing pages? - #5 by sijo.
The headings are ‘synchronised’ insofar as you are using a grid for each element (heading, paragraphs, etc.). However, what I have not yet solved for is how to have the heading numbers synchronised when using automated numbering of headings.