Taking away an aspect of someone's psyche generally doesn't make them better at stuff that is incredibly complex and chaotic like modern war is.

A factor in why the Soviet Red Army, Vietnam People's Army, and Chinese People's Liberation Army proved better at winning wars of attrition against enemies like the US, Germany, and Japan. The US, Germany, and Japan since the WW2 era have dosed their frontline soliders on high doses of amphetamine. Methamphetamine was first used by the Japanese military, it was also adopted by their German allies who gave it to all their soliders in WW2. For Germany methamphetamine was a major factor in offensives collapsing, German military units would push non stop without sleeping for days, after a week their frontline units were hallucinating and having full psychotic breaks deep behind enemy lines.

https://time.com/5752114/nazi-military-drugs/

https://www.scmp.com/magazines/post-magazine/long-reads/article/3051418/how-world-war-ii-got-japan-and-us-got-hooked

The US at the same time had discovered another amphetamine, dextroamphetamine aka dexedrine and its more potent form adderall. Returning US soliders after WW2 were so addicted to it that dexedrine was sold in grocery stores and gas stations until it was finally made prescription only in the late 1970s early 1980s. It was used by most Americans and we just blackholed the fact that the US issue with amphetamine abuse started as a result of pumping all US service members full of it in WW2.

https://www.wired.com/2003/02/the-u-s-military-needs-its-speed/

Dextroamphetamine is still heavily used by the US military for air force, navy, and special forces— discussion of it only comes up after US fighter pilots lose their shit after being kept awake flying combat air patrols for over 48 hours, start hallucinating and drop all their ordinance on Canadian ground forces. The US also feeds their JSOC forces (seals, delta, etc) a cocktail of nandrolone (19-nortestosterone) and dextroamphetamine, which goes a long way to explaining the insane violence (murder sprees, dismemberment, decapitation) that they are always getting up to when terrorizing the communities living within 50 miles of Fort Liberty (formerly fort brag). Like what do they expect after pumping already violent men full of anabolic steroids and amphetamine at the same time?