Marshall Zhukov went through Russian troops like we went through gasoline.
I don’t think “military genius” applies to him.
Promotions were very fast after Stalins purge of general officers.
He was very adept at deep operations as the Japanese first discovered in Manchuria when Zhukov kicked their arse. But as you mentioned much easier to be a “military genius” when you don’t have to worry about casualty figures unlike the Western Allied commanders.
When it came to getting his men slaughtered to achieve a goal. he makes Grant look like a piker.