You are right in one major issue - these two tirans couldn't share the same Earth for a long time. But on everything else we can argue
1. The difference between the Nazi and Commie is not as big as you think.
Racial superiority vs. Class superiority, that's all. This is theory
In their practical application both regimes were so similar. From mass propaganda and youth's indocrination from their suppression of any dissent to the foreign aggression - they were like brothers!
Do you know that Gestapo and NKVD used to have joint seminars to share their methods and findings, that more German communists of high rank have been destroyed in Gulag than by Gestapo? They were much better pair than the trio FDR-Churchill-Stalin, don't you think?
2. The Germans and the Russians didn't hate each other before the WWII! The Russian Csars after, I believe, 1765, were German by origin, including Ekatherine the Great. Nicolas II and the Kaser Wilhelm II were cousins. Ethnic Germans were serving in the highest state and military posts of the Russian Empire including prime-minister's. When the Germans were occupying some russian territory in the WWI, they behaved, more or less.
So, when they advanced again in 1941, many people, including the Jews(!!) didn't want to flee, saying:"The Germans are civilized people, why should we fear them?"
3. Are you aware of the role the Soviets played in the restoration of the German War Machine in the 20-ies? Of the visits made by the future Wermaxt generals(including Guderian) to The Red Army training centers?
4. I have started to climb mountains in the USSR more than 30 years ago. At that time, we still had some old instructors who fought in the war in the Caucasus mountains. They told us - EVERY officer and many men of the German alpine division had an opportunity to visit these mountains before the war! There were climbing there with their Russian friends. So, when they came back in 1942, the fights were often personal - the enemies were often known by their first names!
Of course, the brutality of the Nazi occupation and the bitter fighting has changed all that. But it wasn't always the case...