Jeskai Ephemerate's key artifact is Bender's Waterskin for mana fixing, and while Annul's impact is somewhat narrow, it still answers that piece and any other artifacts that show up, while Steel Sabotage provides flexible artifact disruption or a bounce effect. Deem Inferior is weak since their best creatures (Mulldrifter, Murmuring Mystic) aren't must-answer threats on their own and putting one second from the top or on the bottom of their library doesn't address the Ephemerate-driven value engine. Sleep of the Dead is similarly low-impact against a deck built around repeatable enter-the-battlefield triggers rather than a single big attacker. This matchup comes down to counter wars over Ephemerate and Augur of Bolas/Mulldrifter value creatures, so prioritize Counterspell and Dispel to disrupt their loops while advancing your own clock.