Per the opponent's own strategy notes, their threats (Hearth Elemental, Eddymurk Crab, Sunderflock) are mana value 6+ on the battlefield regardless of cost reduction, so cheap answers like Requiting Hex (mana value 2 or less only) and Witherbloom Charm's destroy mode (mana value 2 or less only) cannot touch them; trim one copy of each since you have four other removal spells (Vraska, Bitter Triumph, Garruk) that aren't restricted by mana value. Outrageous Robbery lets you generate card and mana advantage to race their grindy cantrip plan. Decorum Dissertation adds a repeatable card advantage engine to keep pace with their filtering. Keep Bitter Triumph and Vraska in since they can actually answer the big Elementals.