Teferi, Time Raveler is the critical threat in this matchup — it shuts off instant-speed cascade from Violent Outburst, forcing you to rely solely on Shardless Agent at sorcery speed while leaving you exposed to Fatal Push and Solitude in response. Inevitable Betrayal is your best answer, stealing Teferi or Overlord of the Balemurk for zero mana off a suspended start, and Mystical Dispute provides cheap countermagic for Consign to Memory and any blue permanent they try to resolve. Subtlety comes out because bouncing their creatures to the top of library barely slows down a deck built to loop Phelia and Ephemerate indefinitely, whereas the matchup is really decided by whether you can land a protected Living End. Cycle aggressively to fill the yard, then commit your cascade spell when you can back it with Force of Negation or Flare of Denial, and watch for post-board Nihil Spellbomb — hold a Force of Negation specifically for their attempt to exile your graveyard on the stack.