The Soviet Union likely would have defeated Germany eventually, on its own, or at least forced it to end the war. Yet maybe Western Europe would still be under occupation? Yet would Britain have allowed that? Would it fight on?
Had Germany not invaded the Soviet Union then perhaps someday they could have overwhelmed Britain. Still, the Royal Navy had kept the smaller German Navy at bay and the Royal Air Force prevented Germany from gaining control of the skies, even before the invasion of the Soviet Union. So who knows? It may have dragged on to a stalemate, and ended in a peace treaty with Germany still in control of France, etc. Yet then somebody would invent the atom bomb and tilt the balance, and perhaps force a new solution (with or without using it).
Yet in these alternate histories, what would happen with Japan? Would it still have attacked the U.S? If Germany had not invaded the Soviet Union, would the Soviets have attacked Japan? So complex.