The biggest problem with this, and its a problem I genuinely dont have a solution to, is sideboarding
Its important to note that even if an opponent is tasked with defending a battle, the person who cast it is still both its owner and controller
Vexing Arcanix was also not really about milling, but anyone who's every played Ice Age sealed knows how often you use it to mill out people in Limited games (if they don't die to the damage first that is)
Anybody whos ever played Vintage Cube knows just how powerful a mana advantage can be
Keep an eye on Modern Horizons 2 draft boosters for Esper Sentinel, Urza's Saga, and Ragavan, Nimble Pilferer, lands that start with , Pay 1 life, Sacrifice (these are fetch lands), or anything with Incarnation in the creature type line
Lot of Madness going on here, and in fact the event was a finals match between two Mono Red Madness decks