The key card is present but its support is thin.
Prioritize useful support such as Infestation Sage or Sanguine Syphoner.
Attack with a creature that can profitably trade or survive, then cast Goblin Boarders in your second main phase. Perforating Artist can stay back and still receive its end-step raid trigger.
Your deck enables the plan but is losing the early turns.
Take a castable early creature or efficient answer before another expensive payoff.
Raid needs an attack, not a combat hit or a surviving attacker. Do not make a disastrous attack merely to grow Boarders when a normal creature and a stable board would be better.
The support is missing
Favor independently useful creatures and interaction if the narrow support does not arrive.