Decent backup camera that actually weatherproof?

Guys, I have a truck bed camper with barn doors, so I had to remove my tailgate. I bought what I thought was a decent solution from camerasource.com. It was an adapter kit with camera that I could mount on the rear of the camper, near the top. Worked great.....until the first Carolina rain storm. It was completely full of water. Opened it up, drained the water, allowed everything to dry, and it still worked. Gasket looked good, everything was nice and tight, so I sealed what looked to be the only entry point where the cord enters the body with silicone. Reinstalled, and again...filled with water. I contacted camera source, they sent me another. For the hell of it, I sprayed the outside of this one with flex seal...couldn't hurt, right?

Full of water just like the last damn one. I can't figure out how the water is getting in.

Anyone know of a 4-pin remote camera that actually works? This is a 2019 3rd gen.