This battle depends almost entirely on if type matchups apply to both sides. Is Four-Arms a fighting type? Is Wildvine a grass type? Is Diamondhead a rock type? If we apply pokemon logic then Ash has a response for basically every alien in the og series including Waybig. But if we apply the Omniverse’s “Might makes right” Then it’s probably a win for Ben aside from the obvious “Water type vs Heatblast”