I am just curious what the state of android auto alternatives are at this point.
As much as I would like to use GrapheneOS I would find it quite hard to part with Android Auto / Apple CarPlay. I am not expecting Android Auto to be one of the apps to be available in sandboxed gapps, but I would like to see a viable alternative that is better than using OsmAnd with my phone mounted to the dashboard.
Android Auto and Apple CarPlay have their own protocols that the onboard units have to implement. So if you want a third option, the car vendor(s) would have to implement that as well. Which is unlikely. Those who do not want to bend to Google or Apple usually just force their own shitty onboard system in your face.
The closest you could get would probably be using an Android tablet and find a good spot to add it to your interior. But you will not have any integration with the car. If you want to tinker, you could use a bluetooth OBD2 dongle to stream some realtime engine information, but there is no generic way to hook into the multimedia systems (typically).