If the allies had sided with Germany against Russia the world would be a much better place. Every single stakeholder in WWII would have been better off. Hitler's ambitions are not to my taste but he had legit concerns all around; Jews, Russia, communism, etc. Russia would have been reigned in early, no Cold War, no nukes, no globohomo. The allies could have inserted themselves into Eastern conflicts and modulated Germany. Obviously just speculation but that's my impression.