I wonder if Hitler took Moscow, if Stalin would have survived, or would he have been deposed, perhaps by Khrushchev, who even then harbored ill-feelings towards Stalin.
Then let’s assume the Soviets eventually turned the tide, you would have had no Hitler, and at least perhaps a much more benign Soviet leadership.
Nazism and Communism were both cauldrons of evil, though Nazism more intensely boiling. This is tantamount to a chaos theory question.