This grindy lifegain deck leans on resolving key noncreature pieces like Ajani Resolute and Lunar Convocation, so an extra Duress to strip those before they generate value is excellent (it can't take their creatures, including Liliana the Faultless). The extra Deadly Cover-Up gives us a second sweeper to reset their wide board of small lifegain triggers (Hinterland Sanctifier, Haliya, Guided by Light) before they snowball. Strategic Betrayal makes them exile a creature of their choice plus their graveyard, denying recursion targets for effects like Moseo, Vein's New Dean's Infusion ability. We keep Spell Snare in, since many of their key pieces sit at mana value 2 (Amalia Benavides Aguirre, Enlightened Confidant, Ajani Resolute, Lunar Convocation), and instead trim card draw (a Winternight Stories) and a Theorix Charm, since proactive disruption and a sweeper matter more against their incremental value engine.