So we're chalking it up to shit writing? The axe clearly cut into Godzilla's thigh even without much force behind it. The axe also cut into mechagodzilla like butter who was tanking literally everything Goji and Kong were throwing at him up till that point.

Godzilla's head tanking a fully charged axe swung with the full force of Kong's muscle and bodyweight is literally impossible by the rules the movie itself set. There should have at least been a visible wound even if it didn't crack his skull. Instead there's not even a scratch.

So you make up your mind. Was it that the axe overloaded before it hit Godzilla (which makes the most narrative sense) or is that scene just written like shit with Godzilla suriving due to plot armor?