The key card is present but its support is thin.
Prioritize useful support such as Greasewrench Goblin or Prowcatcher Specialist.
Develop Rocketeer Boostbuggy and Boom Scholar, then use the Scholar's generic discount on a different permanent's exhaust. An animated Boostbuggy can attack for Treasure while creatures stay available.
Your deck enables the plan but is losing the early turns.
Take a castable early creature or efficient answer before another expensive payoff.
Exhaust is once per individual ability, not once per turn. A discounted activation still needs every colored symbol, and Boom Scholar does not reduce its own exhaust cost.
The support is missing
Favor independently useful creatures and interaction if the narrow support does not arrive.