GrapheneOS does install Android Auto, but Android Auto only shows apps installed from the Play Store. Even though GrapheneOS is working on spoofing that, it still won't help as Android Auto requires closed-source libraries and thus no app from F-Droid can include it.

Either way, my Pixel 7 has a weird thing, both with OsmAnd and CoMaps, where the location updating is janky during navigation and the speed readout is stuck on 5mph. In OsmAnd I can fix this with a setting which lets me use 'Android API' instead of 'Google Play Services' for location data. Maybe I can open an issue with CoMaps to add that option.