IIRC, the 7th Infantry Division were the main US force in the Aleutians. After the archipelago was secured, they went on to fight at Kwajelin and then participated in the liberation of the Philippines.
I think that the 7th ID was fresh from desert warfare training when they were committed to the Aleutians. They were slated for North Africa and were not equipped for arctic warfare.
On Attu they couldn’t even get up the ridges where the Japanese were entrenched because the draws & valleys were so marshy from snowmelt. They disassembled jeeps & hauled them up by hand, reassembled them & used them to power tow-ropes to drag supplies up to the summits. Incredible ingenuity under fire.
The Army didn’t do everything wrong. They at least had the foresight to recruit Inuits, Trappers & Fishermen who had knowledge of the terrain into “Scout Units”. These guys imparted valuable survival skills to the troops & help them adapt.