Hi,
I've had numerous reversing cameras over the years and here's what I've found.
Don't go wireless, signal can be interferred with when you are carrying loads in the back. I sell welders and these were shocking for it.
Rear vision mirror mounted screens, limit mirror usage and tend to be dark shaded which makes the mirror difficult to use with window tints.
Rear vision mirror mounted combined with dash cam, these are a little better as you can have just the rear camera come up there but then the same problem as above.
Radio with rear camera, I use this currently and this has become my defacto to the rearview mirror. Takes some getting use to but you need the 7" screen minimum and a good quality camera and camera position.
The best I have found was a windscreen mount rearview on it's own that was in the right corner of the screen next to the drivers mirror. I had a 6" screen which was great but hard to find online. Camera was hard wired but came into the cab with the canopy wiring. Camera was powered through the screen which ran a seperate wire to the reversing switch on the gear box. This meant I could switch the camera on without needing to be in reverse, handy when checking a load on the trailer. A bit of a faff to wire up but I drive 60+ k per year and fitting it when it's new and having it for 4 years makes it worthwhile.
My 2 cents worth.