Rest in Peace cleanly shuts off their reanimation of Atraxa or Griselbrand by exiling all graveyards and keeping them clear, while High Noon limits players to one spell per turn to disrupt their combo. Spell Snare picks off their two-mana pieces like Goryo's Vengeance, Psychic Frog, or Faithful Mending. Day's Undoing is far too slow and gives them a fresh seven-card hand, so it comes out; Prismatic Ending trims down since sorcery-speed nonland permanent removal doesn't answer graveyard reanimation and you need mana up for interaction instead. Keep Solitude and Teferi, Time Raveler in to fight through their Ephemerate/Atraxa value engine.