Izzet Spellementals leans on Prismari Charm, Traumatic Critique, and cantrips to grow Hearth Elemental and Eddymurk Crab, so proactive discard with Duress strips their key interaction or payoff before it resolves. Ghost Vacuum can exile cards from their graveyard to deny Eddymurk Crab's cost reduction and Hearth Elemental's discount. Seam Rip whiffs on their bigger threats and Erode is reduced since most of what we want to kill isn't a creature until too late; keep enough removal for Hearth Elemental and Sunderflock. Lifegain engine stays fully intact to stabilize through their incremental value.

UR Aggro wants to go wide with cheap cantrip-fueled threats like Elusive Otter and Slickshot Show-Off. Pyrrhic Strike stays in the sideboard: its creature mode only destroys a creature with mana value 3 or greater, so it misses their cheap threats, and blighting just lets you choose both modes rather than kill smaller creatures. Their main deck also has no artifacts or enchantments for the other mode to hit. Seam Rip stays in, since it exiles nonland permanents with mana value 2 or less, which covers Otter and Slickshot Show-Off. The extra Starscape Cleric makes them lose 1 life each time you gain life (once per life-gain event, regardless of the amount), which matters against a deck trying to burn us out. Keep the full lifegain engine intact since Amalia and Haliya outlast their velocity-based plan.

Dimir Midrange relies on Kaito, Bane of Nightmares and Requiting Hex plus efficient removal; Duress pre-emptively takes away their removal, Kaito, or a counterspell before it generates value, though it can't take their creatures such as Enduring Curiosity. Ghost Vacuum can exile cards from their graveyard, including a dead Enduring Curiosity before it comes back, and it denies any other graveyard value. Seam Rip and Erode are weaker here since Kaito dodges mana value 2 or less, and Erode hands them a basic land that ramps their deck; cut both. Our lifegain core remains the best way to out-value their incremental card advantage.