The key card is present but its support is thin.
Prioritize useful support such as Leonin Surveyor or Nesting Bot.
Trade Nesting Bot and use its Servo to keep a board. Cast Dune Drifter with X high enough to return a useful graveyard card; Embalmed Ascendant later rewards creature deaths at max speed.
Your deck enables the plan but is losing the early turns.
Take a castable early creature or efficient answer before another expensive payoff.
Do not spend the whole game waiting for max speed before interacting. Dune Drifter's X is part of the casting cost, and the returned target can be exiled before its entry trigger resolves.
The support is missing
Favor independently useful creatures and interaction if the narrow support does not arrive.