You have the payoff but too few ways to activate it.
Look for Prickly Pair.
Pair adds a Mercenary whose power-boosting ability Ertha Jo can copy, supporting a large attack without another card.
Your synergy is already working but you keep falling behind.
Take an early play or answer before another expensive reward.
Ertha Jo copies activated abilities with creature or player targets, not ordinary creature-targeting spells.
The support is missing
Favor castable creatures and interaction if narrow support does not arrive.