Good points, after Germany committed to full unrestricted submarine warfare to besiege the UK, the USA had to intervene in that course of events or lose its key ally.
so foolish of Kriegsmarine and H to lose the battlecruisers and makes First/Second Happy Time seems like a diversion of resources, then there may have been a more credible medium/long term threat to the allied lifeline without these unsustainable efforts
With a timely and immediate entry of the US into the Atl. war (as actually occurred), they deployed tons of planes and ships, and technology, that wasn’t effective at first but needed to mature and develop to defeat the submarine threat on one hand, while demolishing the Japanese Navy with the other.
