Yeah with 1 plate, and i think most often in the back, a front camera alone are useless against any oncoming car then, a rear camera would give you a fighting chance at least.
Though you guys are hampered in the fact that it seem like US license plates are not supposed to be easy readable, the EU plates are much more easy to deal with, though even here you often miss a plate, and for that to happen it dont have be the dead of night on a rural highway.
There are technical limitations to all dashcams in the hardware they use.
The good thing is a front camera, pretty much no matter how cheap hardware it is made off, will log your driving all the time and in most conditions, so if you drive nice, then what ever happen off camera cant really be your fault.
So that in itself will fend off many a outrageous claim made against you.
Yes i have my phone mounted off a small piece of fixed glass on the driver side door, so i think turning it on with the selfie camera recording it should be able to get a good look at anyone at the door.
Though my setup are a bit stiff so it cant be aimed much more than parallel with the glass but i can angle it upwards a few degrees too, other more flexible mounts might be better.
My phone holder are made up of a Brodit universal holder that is then mounted to the main parts of the holder that came with my Samsung galaxy 2 phone back in the day.
This Samsung dock look like a modern version of the one i have / more streamlined.
I then ripped off the original "tray" as it was way too small for my modern larger phone, and also USB mini VS the USB C on the new phone, but the Brodit universal dock covered all that.
The 2 parts are then glued together, so the adjustable ball joint are still functional.
This is a pic of a car like mine, you can see the little fixed glass on the very front of the front doors, similar there is a little on the rear doors too, this is where i have mounted my side facing dashcams.
In the front the dock do not impede view to the mirror, you look at that thru the main glass,,,,,, TBH i dont know why they put a piece of glass there, would have been cheaper to just do metal.
I will see if i can remember to snap a picture of the dock on my door tomorrow, and do a test recording with the selfie camera.