Up until the point Hitler attacked the USSR, the Communists here at home were staunchly resisting Roosevelt's efforts to assist Great Britain in the war. Suppose Hitler had instead concentrated on finishing the Brits off, one day during the Battle of Britain the Brits were down to just six Spitfires, stayed away from attacking the Soviet Union and allowed the American Communists to continue retstraining Roosevelt's efforts.
Japan would still have attacked Pearl Harbor and Roosevelt could have responded exactly how he did with no change in the historical record until the Marines landed on Tarawa. After the stuggle to take Guadalcanal, the debacle, the losses, on Tarawa would have been too much for the people to take, especially with the Communists continually agitating for withdrawal and surrender in the background. They would have forced Roosevelt's hand to instead sue for peace. Unfortunately for Hitler, after June 22, 1941, every Communist in America wanted Roosevelt to declare war against Germany.
Some inner idea or concept, I hate to use the word 'force', drove Hitler to behave impetuously and hastily in planning his next moves. There are numerous records of his telling associates and acquaintances he had to move quickly for he knew his time on Earth was sharply limited. That was part of the reason behind his attacking the USSR and the leaving the Brits dazed, bleeding, on the ropes, ready to collapse, but still unbeaten.