Hi @avatar, welcome to the forum 
I’ve previously written about some of the most important parameters in the “camera” toggle section of this post - hopefully that’s helpful.
Different cameras have different tradeoffs that work better or worse for a given scenario, and a “good” camera for one use-case is not necessarily good underwater. That said, there are very few (if any) camera sensors that are specifically designed for underwater use - it’s more a question of whether you or someone else should go through the selection process to determine a set of features that will work well together in that environment.
It’s definitely possible to find a camera that happens to work well underwater without it being advertised for that, but the ones that are sold as underwater cameras are more likely to have a good selection of the available features at the price point they’re sold at.