but Android Auto does need some work on the car OS side to operate
Yes, I was just arguing against Android auto and Android automotive being the same or similar thing.
Android auto is your phone projecting to your cars infotainment system. This can work independent of what the cars operating system is. Android automotive is Android “optimized” as an operating system for a cars infotainment system.
Android auto runs on your phone. Android automotive runs in your car.
See my other comment