Goku has spent his entire 50+ year life fighting. He fought an assassin that was capable of killing a healthy adult with his tongue as a mere child. During the Namek saga, he was so fast that everyone thought he wasn't moving at all. In the T.o.P., upon unlocking Ultra Instinct Sign, he managed to shake the entire world of void, a world filled with infinite nothingness. How can Goku shake an infinite concept that has nothing in it? Simple. Fill said void with your own energy and shake that instead. Goku is much more powerful than people perceive him to be, and he isn't someone you want to fight unless you KNOW what he's capable of.