If Hitler wasn't a dumbass, the Soviets would have been happy to split the European and African spoils, while uniting to turn on Japan and secure Asia as well. Then North and South American would have been targeted next.
The only reason the Soviets nobly turned their guns on the Nazis was because the Nazis started slaughtering them.
Hitler was told that it would take another year of war production to get the victory over Russia that he wanted.
Yet Hitler went ahead with it, fearful that waiting another year would give Stalin more time to build up to attacking Germany, instead.
This belief that “now was the time” was enhanced by the poor performance of the Soviet Army against Finland and Poland, as well as the Soviet aggression against Romania (The Bessarabia Ultimatum).