Another possibility, maybe easier or more sustainable, would be to hire the employees who built the harnesses and interconnects for the car’s entertainment comp

Another possibility, maybe easier or more sustainable, would be to hire the employees who built the harnesses and interconnects for the car’s entertainment computer. Tell them to build a drop in Raspberry Pi-powered replacement with a custom, basic firmware that only does CarPlay or Android Auto, and call it a day. Or maybe the result is a Frankenstein creation where the original controller takes care of the driver’s dashboard display, but the entertainment display is Pi-driven.