Over 20 million Russians and Ukrainians perished in the war, a good many of them due to Stalin's blunders. As an example in spite of warnings from England about attacks and German strategies as revealed by Enigma decrypts he routinely ignored them.
For some reason I’ve always had a fascination for the war within a war between Hitler and Stalin. It was an incredibly brutal war with atrocities committed by everyone to everyone. The scale of this conflict, and the staggering losses, defy imagination.
Stalin was an absolutely ruthless dictator, willing to force his subjects to pay any price. Both dictators cared not a whit for the lives of their soldiers or their peoples.
This conflict was also filled with great ironies, most notably the two related to the Non-Aggression Pact. The first irony is that Stalin, the man who trusted no one, trusted the one man no one should have trusted; Adolph Hitler. Stalin’s trust that Hitler would not attack him led to a good deal of the Soviet losses in the first year of the war. The second irony is that Stalin entered the Pact in the first place in the belief that the Western Allies were not serious about fighting Hitler themselves. Stalin believed they just wanted the USSR to defeat Hitler at the cost of copious amounts of Russian blood. So he cut his deal with Hitler with the intent that it would keep him from being drawn into the war. But by entering the Non-Aggression Pact, Stalin gave Hitler a free hand to defeat France, and then turn on him. Thus, it turned out that the only way to defeat Hitler was for the USSR to do all the heavy fighting. And in the end, Hitler was defeated at the cost of copious amounts of Russian blood.
There is no way to romanticize what took place in the East. The Soviet Socialists were monsters and so too were the invading National Socialist monsters.
It's difficult to comprehend the suffering which took place in the East, particularly in those regions where massive pitched battles took place between the two godzillas.
Then there was the partisan warfare; pro-Soviet, anti-Soviet and mixed groups of assorted criminals and deserters.
For the civilians in those regions, it's probably best to not know too much about what they did in order to survive.