Have you got an spare DIN slots on your dash? You can get fold out dedicated screens that are neater than a clip on separate monitor.
Beware of the chinese Android head units, they are pretty glitchy, distracting to use and mine ran really hot. Mine also didn’t work with the Clarion camera already fitted to my van, they claimed the camera was incompatible but I suspect the radio was faulty. (I went for a Sony Android Auto unit in the end but they are a bit spendy)
Mount the camera high looking down, mine has a 100 degree angle to I can see from the towball right up to the following traffic. A number plate style is better than nothing but not uch use when you are trying to gauge distance from a brick wall.
Wired is better than wireless, I have one of each on a dual input screen, both good enough quality but the wireless does drop out occasionally. If you want a permanent rear view option you will still need to run a power lead back there anyway. It might also cause issues with bub failure warnings if you tap into the reverse bulb for power.