I have a Eonon GA2170. It's one that has issues with screen brightness. I actually replaced the screen with the screen from my old Pumpkin, which died after ~3 years.

You can stream OBDII info, but I never have. I really just use it for podcasts, GPS, Pandora, and the reverse camera. I believe some can connect via mobile data, but none work with Verizon, so I just use my phone as a hotspot.

There's an XDA forum for them, but I never really dug into them because no one was doing anything for the models with the layout that I wanted.