Pick the two counterfactuals:

- would have USSR marched on Berlin without the US landing in Italy and Normandy ?

- would have the US landings be successful if the Nazi army from 1940 had remained in Western Europe because it was at peace with the USSR ?

The answer for #1 is an obvious yes, and for #2 it's unlikely to be one.

WWII in Europe was won (or rather lost, by the Nazi who betrayed their totalitarian ally) on the Eastern front, and it's not a controversial take.

> Further, war is fundamentally economic, so trying to argue that some less efficient means of conducting it is somehow superior is mind-boggling.

This is nonsense. The US lost a war against Afghanistan, not because the Talibans were more efficient (they weren't, they lost orders of magnitude more soldiers than the US). Thinking about war as an economic thing is exactly how the US keeps losing all its wars since the Korean War.