Power inconsistency.
In a lot of movies which involve superhuman power, the characters sometimes forget that they have powers or their power keeps dropping as the movie goes on.
In the boys series on one season they have certain power and in the next that power completely disappear.
Homelander can tank pretty much anything, which vought themselves said but at the same time Queen Maeve stabs him and he starts bleeding.
Black Noir took a blast to his face and from machine guns and healed without any issue but in the end he dies from knife attack. He also forgot he can fly.
The Deep is insanely durable as he can effortlessly withstand the pressure at the bottom of Mariana Trench but in the end easily dies after a massive squid shove his tentacles in his Ahhh.
Thor, who is known as the god of thunder gets electrocuted by a tiny device on his neck.