It's not a question of higher being, just that a universe where the effect predates the cause can't hold. God is not less omnipotent because they can't make a round square.

So this would mean that logic exists outside our universe, and since God can't change logic, it's an even higher power than they are - right? But why isn't God bound by logic regarding e.g. creating matter/energy?

It seems it all comes down to God having to follow rules beyond their own design and power, which flies in the face of them being all-powerful and all-knowing. After all, even if evil must be an option, they could have created the universe such that no being would ever choose to do evil - they already knew the choices everyone would make when they created the universe!