That is very disappointing. Losing functionality and poor sound quality is not acceptable.
That reinforces my view that if you add a CarPlay unit and install it with a bit of care to hide the cable, it is the best solution. And miles cheaper.
You also retain the original screen which I use for phone calls as it seems to work better. No problem with music quality as you are still using the Inveray connection but with the ability to control it from the CarPlay screen.

I think I will wait for a cheaper more reliable set up!