Queries like this should really be posted to the "What Should I Buy?" sub-forum.
In any event, as a long time dash cam using pick-up truck driver I would suggest avoiding very wide view rear cameras. You want a "medium" wide viewing angle (120-140º horizontal AOV at most) that can better capture what is happening behind you such as license plates and driver behaviors.
The camera should be mounted as high as possible in the center of your rear window. In my case, I have a sliding glass center panel so mounting the camera directly on the glass would prevent me from opening the window. I attached an aluminum plate to my headliner and have the camera on a mount that allows the lens to peek down from the headliner without touching the glass.
There are many options available these days and I can't really make a recommendation but for now I use a Viofo A119 V3 for my rear camera as the viewing angle is just about perfect. I get good coverage of my truck's bed for monitoring cargo (especially when parked) and I have good coverage on either side of the bed and behind me.
Not really a big problem, but a FYI for future reference.
Maybe post again over there and get some recommendations on the latest cameras? Look for something with a Starvis 2 sensor and a lens that best meets your needs.
There are some excellent two channel models available. For a single channel rear truck cam look into the new VS-1 from Viofo. It's tiny and I think has much potential for a rear pick-up truck camera. It happens to be on sale!
VIOFO VS1 Mini Dash Cam, 1440P Hidden Design Dashcam, Free 32GB MicroSD Card, 5GHz Wi-Fi Voice Control Front Car Dash Camera with GPS, HDR, Night Vision 2.0, 24H Parking Mode, Support 512GB Max