
If he literally knows everything, just imagine what he could do if he turned evil and decided to conquer the multiverse.
He would know exactly how to accomplish any goal he had.
He would know exactly what to say to convince anyone to do or believe anything he wanted them to.
He would know the plans and actions of anyone who would attempt to stop him and exactly how to counter them.
He could easily gather the Super Dragonballs and make a perfect wish. He could convince the two Zenos to erase each other, after erasing all of the gods and angels for good measure.
He would never have to actually fight anyone, because he would know precisely how to avoid the fight in the first place.
There would be literally no one that could stop him.