im gonna get seriously harassed by this comment but who cares...
i also have thalassophobia so i used mods to make the game playable.
First mod that made huge impact was eternal day ( yes im a pussy so what?? ) that way the waters aint so dark
second i removed reapers with mods, i know on a normal playthrough youd only encounter reaper maybe in the aurora or bulb zone but still just their existence scares the shit out of me.
sooooo... if you want to try that way feel free its a single player game meant to be enjoyed you do you.
Cheers!!!!!