That’s why I say the best-case scenario was Hitler taking Moscow, leading to Stalin’s ouster and perhaps replacement with a Non-Bolshevik government that leads Russia to victory along with the Allies, No more Hiter, No more Bolsheviks.
I used to think the same. However, after reading a bio of Churchill recently, I learned that the allies were quite worried that Stalin would make peace with Hitler and drop out of the war. Stalin had hinted that it was a possibility. It took so long for the allies to get ready to take the fight to Hitler, that they worried they could not defeat Hitler if Stalin made peace with Hitler. That's why they kissed Stalin's ass and covered up the Katyn massacre.