I've investigated this. There seem to be two adapters:

https://carsifi.com/
https://www.indiegogo.com/projects/aawireless#/

The second one seems to be the superior solution, but they're in production hell right now with respect to parts availability. The chip shortage is a problem for them, and they've apparently had to redesign their motherboard to allow them to use chips from multiple vendors.

Anyway, once the supply chain mess settles down, I'll almost certainly get one of these things for our VW GTI, which supports USB-based Android Auto.