The pirate war is a secondary and to us not existential theater? its going to be us sending a battalion at most due to sea lift limitations and only professional troops anyways?
I'm envisioning us using the fleet of smaller merchant shipping we have been steadily and explicitly building in part for this task, coordinated to move multiple battalion scale units. Those ships can definitely move a platoon of infantry, artillery or supplies for same, and we have what, a few dozen of them by the time the war starts? Not to mention the 3? Monitors that we will have finished in the next two turns, which could also move at least a platoon each, plus whatever shipping we continue to crank out for both trade and military transport purposes. That is at least two Battalions, and with it going to be at least in part an island hopping campaign that requires us to deploy multiple units to take and hold territory.
We are going to be deploying way more than just those two battalions to the island hopping campaign.
And that's not even including the Zeroth Reich area to the west, which is not a small island we can take with just a single battalion covered by a Monitor. That is likely going to need to be a full Regiment scale deployment, possibly more, and it was the payment we were promised by Crete for our aid in the war. And since it isn't an island we can surround to deny naval access, we have the strong possibility of skilled and well armed combatants retreating into the west, so we have to heavily garrison it to boot.
As for Westcom, while I agree that they are a much larger threat in the long term, they also have their own problems and are not a threat in the short term. They need to win their current wars decisively, then invade their neighbors to the south, win that decisively, and only then can they come for us. That is at least a year of work, even if they have absolutely crushing victories, and we can help delay that further if we have any resources to spare.
Meanwhile we have the pirates, who I'm honestly surprised haven't raided our coasts yet. They are known for taking a city for several days, shipping off the population in chains, then burning whatever they cannot take. And while we can put up a fight they will likely have local superiority in both quantity and quality to any garrison forces present, while it would take us days to form up and get an adequate response to the location. You are correct the pirates are not an existential threat like Westcom is, but you are incorrect about the comparative lack of threat they pose.
It's only a matter of time until we lose some villages to them, and possibly even a larger city. I'm honestly surprised we have not already had such a thing happen, and likely the only reason is the pirates are going for easier targets first. That will cut into our labor pool, our production of trade ships, our trade income, our prestige, our political capital and so on. It won't kill us, but a couple times of that will certainly hurt us and make fighting Westcom much harder, not to mention bolstering our internal opposition. But attacking the Pirates home territory will force them on the defensive and help prevent that from happening.... if we can put enough force behind it.