The key card is present but its support is thin.
Prioritize useful support such as Wary Watchdog or Patchwork Beastie.
Let Wary Watchdog's surveil find a missing graveyard type without throwing away needed lands. With delirium active, Beastie Beatdown puts counters on your creature before it deals damage.
Your deck enables the plan but is losing the early turns.
Take a castable early creature or efficient answer before another expensive payoff.
Delirium needs four card types, not four cards. Patchwork Beastie is unable to block before then, so an opening built around it still needs a realistic way to survive.
The support is missing
Favor independently useful creatures and interaction if the narrow support does not arrive.