I always heard, but maybe you could shed some light on it. But what I heard in the past, is that in instances where Russian soldiers themselves, did not feel they were justified in invading other countries, traditionally did very poorly on the battlefield. Finnland in World War 2 being a classic example of it. Thoughts from former Army guys? :-)
USAF, retired.
I can’t remember what they were called but the Russians had squads that were close behind the assault troops and they shot any who hesitated.
Patton was right in calling the average Russian soldier and most of their officers “Mongols”. They were all treated as cannon fodder. It was all about attrition.