Tethered camera

I saw a similar topic but it didn’t fit what I am trying to do or parts I have access to.

I want to build a submersible camera to check SCUBA dive sites from my laptop without having to burn a tank. I have access to some specialized extension hardware which enables me to separate the camera from the laptop by ~50 miles (in my use case I only need about 300 feet).

What camera would best fit my application? Obviously it would need to fit in the enclosure and work well in low light conditions. Planning to use the BR 4" enclosure.

The camera could be USB, HDMI, Display Port, etc. as that piece doesn’t matter.

Needs to be able to:
Stream live from the camera output in digital format
PTZ would be a huge plus
4K or HD…4K would be optimal

Any suggestions are appreciated!