Note; Before I start this post, please note that I'm not affiliated with or associated with any of the products I link. Also note this is NOT meant as an ad in any way, but if the mods see it as one, please take it down. I have NOT tested anything I link so I have no idea if this actually works. Others may test this if they wish but I found this and thought it was cool so I'd share it.
I needed a new stereo for my car so I was looking on Amazon. I found this aftermarket infotainment screen by JVC ( I did not buy it so its not tested).
https://www.amazon.ca/JVC-KW-M180BT-DMR-Capacitive-Touchscreen/dp/B0C26RZ2JZ/ref=mp_s_a_1_2?dib=eyJ2IjoiMSJ9.t68Y3XzW-ifd1-PvcJJOTODcW8x-gBqvFvSDZqXp8LCxfjw4c3Rc7iqXqPxgMzAnHpRZf-X_V51GzN49gI-Oobc-Y5mSw1G82SEWD4nrOtR3i-W9Ve8X1nD45sllQsP6gMDt83ATtMFkSlb9RFqA6nLHOrGa0zCKXdpcx-GRgZDgyy4eBwJW4-r3hI8zeZWXpkdgstgurB2PCZQfcwdIUg.9-Q_2VBHzfz3eO5F9VGCR6c6KxPnMPkSTuoBgKxrLGM&dib_tag=se&keywords=jvc+double+din+stereo&qid=1759887744&sr=8-2
(Its on Amazon.ca, but I'm sure its available in other markets). I saw that this screen has something called Phone Mirroring if you get the JVC app. On Aurora Store, it says it has no trackers and works without Google play services (not tested).
https://play.google.com/store/apps/details?id=com.jvckenwood.jvcmirroring
So my theory is, if this app works, you can have your GrapheneOS phone screen on your car, theoretically making it an Android Auto experience with GrapheneOS. Obviously this would only work in older cars that don't already have a screen and you want to upgrade to one. Like I said, I have not tested any of this so no idea if it works. But it does seem cool if it does work. Once again, I'm not trying to advertise and I'm not affiliated with any of this. Please remove it if you see it as advertising! :)