wtf like she's in 2 inches of water then suddenly off to a raging sea. How fucking forced does it get lol. Even the panels make it hilariously sudden

"But he's a dick so I won't offer him any words of gratitude."

Dude, the manga didn't explain much about his power. His only powers are "Creation" and "Deconstruction". If I remember right, you can only use the elements of what the god has blessed you, and since the MC is the god of medicine, he can't use the other elements you've mentioned. and sure he can make oxygen, but he can't use it to propel himself enough to fight the strong current. I have same sentiments as you before but it was explained in the novel more. And his power needs alot of concentration, he can only create and delete an element as long as he has a vivid image of it, the moment he can't concentrate in his magic, it will fail instantly.

tl;dr his power is useful for creating and deleting "elements" but it has limitations.

That was so retarded. All he had to do was create water like a water jet or wind to propel himself forward to his sister. There was no need to do something grandiose like annihilate the water. Now he's drawn unnecessary attention to himself. And he should've long since been able to take care of the shadow thing by creating some clothing with magic that absorbs light. That's all shadows are an absence of light. Idiot.