How many Red Army soldiers were killed by their own “Blocking Troops”? And how many died because of Stalin’s incompetence and megalomania?
I think you have to break that down to the first phase of the War when the Germans were running roughshod across Russia and after when the Red Army reorganized into an effective fighting force.
The Red Army was not ready to fight in 1941 and most of that was Stalin's doing. His show trials had decimated the leadership of the Red Army, which did not have competant senior officers. He had also neglected the Army's equipment. The high command knew there would eventially be war between Russia and Germany and were working hard to rebuild the Red Army, but were still caught unprepared. Those early horrific casualties can fairly be attributed to Stalin who gutted the Army to solidify his power.
After the German offensive was (barely) brought to a halt in the winter of 1941-42, the Army was successfully reorganized, had identified competent senior leadership and had a personnel and training program in place to provide fresh formations.
Still, the Red Army took horrific casualties in pushing the Germans back. I'm not sure that was Stalin's doing so much as it was the Russian way of war. The frontal assault was still their basic tactic. They bludgeoned their way through strong points. The Russian Army never valued the lives of their troops the way we do and that was as true in Czarist times as well as under communism.
They could afford to fight that way because of their vast population. As soon as a region was reconquered the men of military age were drafted, equipped, trained and sent to the front to replace the depleted formations. I'm not aware of any significant resistance from the people as to how the Red Army fought the War.
It was a bargain for us. Studebakers, aircraft, tanks, Spam, etc. to the Russians, who died fighting the Germans. At the end of the day we only mobilized about 100 divisions to fight the ground war in both theaters.