I didn't see your thread before posting my own, but I have a feeling we're suffering from the same problem.
Backup camera doesn't work after first drive of the day
My backup camera always works the first time I drive the car after it's been asleep, such as parking overnight at home. After going somewhere and parking for at least an hour or so, the backup camera doesn't work when I drive the car again. It doesn't matter if I select camera view from the screen or put the car in reverse. It doesn't come back with standard reset or power off procedures. I've tried disconnecting my Samsung SSD and Blackvue dashcam without success. The only thing that restores it is parking and letting the car sleep overnight. I presume doing a 12V reset would also restore it, but haven't tried.
I'm still under warranty and Tesla mobile service has come out a couple of times to try to fix it. They could not replicate the problem, even though it predictably happens daily. They checked the trunk harness wiring and everything is secure. They checked the connections going to the FSD computer and it is secure. They replaced the camera, which did not stop the problem from coming back.
I figured out that it's related to Sentry Mode, which I presume keeps the car from entering a deeper sleep mode. If I disable Sentry, the problem doesn't occur. That's an unacceptable workaround since the whole point of Sentry is to record while the car is parked.
This doesn't seem to be a fleet-wide problem, otherwise we would have had a flood of people posting about it. It's frustrating that this specific combination of software and hardware in my car is causing this problem, but my neighbor who has the exact same car,(down to production month and VINs within a few hundred of each other) hasn't experienced it.
I have a service center appointment in a few weeks. My suspicion is that they are not going to be able to reproduce it, therefore will have no idea what to fix, and it will keep happening until whatever software gremlin is causing it works it's way out by luck.