All true. Yet it cannot be ignored that the Russians ground down and destroyed the best units of the German army. If it had not been for their stout resistance and the willingness to absorb huge casualties, the American land campaign to retake Western Europe would have been much more difficult and American casualties would have been enormous. Many Americans simply would not exist today if the Russians had not killed so many Germans. Their fathers and grandfathers would have never come home to procreate.
I still say, with a more capable leader, the Russians would have won with a fraction of the casualties.