Yes about the purges and initial ineptitude, but this doesn't address the fact that as the war went on, the Soviets became strategic masters, especially at the operational level, and even improving on breakthrough tactics commonly attributed to early war Germany. It's not true that they won due to "disregard" of their own casualties, this is outdated thinking mostly propagated from postwar German memories.

The "asiatic hordes" is a German-created myth, for example. It was necessary for them, because of their cognitive dissonance that made it difficult to accept being beaten by apparently "racially inferior" enemies. How else could they explain it? Was the enemy outthinking them? Impossible, they were genetically inferior. So it must be that they were simply too many and didn't care about piling bodies and bodies until they won.

Also, the Cold War made it necessary for German officers to show themselves as useful to their new American allies, so that they could provide valuable insight into how to battle the Soviet Union. If they could show themselves to be brilliant, only beaten by an unfair superiority of the enemy hordes, Hitler's meddling, etc, so much the better.