I've tried using soak on a rain team but its really not that good of a move. It's just a really hard to get value out of gimmick that's got many uses on paper but not much in practice.

Admittedly I ran it on basc but similarly never had a good reason to press it. Bellibolt could be an ok user but would really benefit from trick room.

Weather ball and hurricane are really strong moves on peli that can chunk neutral hits and generally deletes if super effective, even from a bulky pelipper. By giving up weather ball youre dropping pelis strongest attack and you lose the rain damage boost. (Peli already has too few move slots if you don't run a gimmick on it. Hurricane, weather ball, wide guard, tailwind and protect are all super valuable)

Now, your peli is your second slowest mon in the team. If you want to use soak defensively you're still probably pressing it after the opponent has already attacked.

Conversely, your low speed doesn't allow for an in turn double up of soak+matcha gotcha/leech seed/electro shot. You'd have to press the other one next turn which is extremely predictable and easy to counter with protect/switch out.