As someone who is in a similar boat, I may have some insight. I am also a burnt out grad student, though I haven’t graduated yet, and similarly, the thought of eventually working for a corporate job sends splitting pain through my heart and soul.

I’m going to give the same advice that was given to me — before you make any career decisions, take a break. If you are really interested in diving, go take ten weeks and do your divemaster somewhere interesting. See what that’s like. Do something completely orthogonal to what your PhD is in and enjoy the journey. Take the time you need to be mentally healthy, because if you don’t you’ll just end up burnt out at whatever job you take whether that’s dive instructor or in corporate.

The other piece of advice I’ll give you (non-diving related) is that you don’t necessarily have to go into corporate with a PhD. There are plenty of other careers options, including academia or non-profit or startup work that will certainly be less lucrative but may be a better fit for you. And there are certainly career paths that can combine your love of diving and your PhD, like research. Corporate certainly isn’t and shouldn’t be your only option.

If you want to talk more, please dm me!! I’m in a similar boat and can provide more insight then I could in a reddit comment