You all can just wire up your own cameras to your own stereo screen. Preferably you have rca or some form of input. Many of them are better quality, or you can get different types like a screen in your rear view mirror. You have flexibility/repair ability and you can keep it on while driving if you wanted. You can place it on the top of your car for a better view, or get a camera with higher FOV. Still can do android auto through USB because your phone just does that.

Its not even hard, its just tucking wires behind the plastic trim, and you have to take apart your dash a little. Maybe its hard to do the screen/stereo if you don't have a wire harness but whatever you buy usually comes with one. Your system can be as cheap or nice as you want, and you can get whatever features you want like a microphone for calls, or a DVD player, USB storage slot for pirated music/movies. You can get some with android auto pre installed if you need that. All the cheap ones feel cheap and slow. I prefer the cheap cartoys vibe shitty os from like a late 2010's high end system. 4:3 screen, lots of nobs, lots of inputs. But solid and doesnt suffer software issues that bug me.

Theres so many accesories for older cars especially if you have a car with a cult following. To make them modernish. Many people still lust over older jeeps, Toyotas, Honda's depending on what kind of car nerd you are, and they have tons of anything you can think of. You can get blind spot detectors and complete dash/gauge replacements if youre lucky.