I am planning to add the ability to export adjustments information from the various apps so that you can sync changes as you suggested. It’s a bunch of work, so it won’t be happening very soon, but it’s a priority.
Please note that RAW Power can work with the Photos library directly (on Catalina), so you don’t need to use the Extension and the limitations that Apple puts on them.
It’s possible to store the adjustment information into DNG and read it back into RAW Power. However, other apps would not be able read or understand the data because the adjustments themselves are RAW Power-only (I can store data that they could read, but they would interpret it incorrectly). I’ll make a note to add that to the feature list.