I replaced the stock apps with better ones from fdroid and a friend’s car just doesn’t seem to like Android Auto from any phone, so maybe the bugs aren’t with the phone?

I don’t use Android Auto either (because it’s 99.9% Google), but I know my car (Merc A220) just sometimes won’t connect to my Fairphone over bluetooth… and it’s definitely the car. Literally pull over, get out of the car, lock it… unlock it, get back in and bluetooth connects again. Not touched the phone… ffs