Like what would powerful wizards be fighting over? There's killing each other. Maybe claiming a powerful relic and it has a set of enchantments to disarm, but your opponent could try and stop you. Of course decking your opponent as a way of saying "none of your magic could compete with me, you lose"

I like the relic idea because you could have a set of neutral defenses that are randomized and even do a thing where each player also adds an enchantment to start the game so that win con is always slightly different each game.