Is this Idiom superpower way too overpowered?

I'm thinking of a power that revolves around the idiom "There's always a bigger fish.". Basically the user becomes the bigger fish. No matter how powerful or better the opponent is, the user will always more powerful and more better in comparison. The only equivalent of a bigger fish to the user is the user themselves. This power also works on multiple things at the same time. Is this way too overpowered?