If by a series of bizarre sets of circumstances the Soviet government collapsed by 1943, say the war goes worse for them in 1941-42 so the regime falls apart after the US enters the war and dips it's toe in the war in Europe, what sort of peace deal would happen as a result then if the Wallies have to conquer Germany and advance East into Poland and beyond?
In the scenario let's say that Leningrad and Moscow fall in 1941 due to a series of bad luck events, but Stalin evacuates and continues the war further East, dragging out the conflict, while the Wallies, concerned about the Soviets getting knocked out of the war prioritize Europe and by using resources historically earmarked for the Pacific are able to invade in Spring 1943 and take and keep a foothold in France, but at high cost. Meanwhile the 1942 offensives in the East strike mortal blows to the USSR and they end up collapsing as a regime in Summer 1943, unable to dislodge the Axis from the Volga/Caucasus area. Still the Axis has too much to hold and the US being willing to throw in more strength into Europe means they are able to attack also in the Mediterranean later in 1943, while the Germans are stretched too thin on occupation duties and costly combat in France to hold everything and by late 1944 are streaming back across the German border. Despite the high cost in Wallied lives they are able to break the Axis, driving Italy from the war and fighting their way into Germany in 1945, and push East into Poland and the Balkans in 1946 as the last remnants of the Nazi regime fall back into the former USSR, chased down by the Wallies. Japan holds out longer, but still is defeated in 1946-47. What sort of peace would result of the Wallies have to do things the hard way themselves without the USSR doing most of the heavy lifting on the ground in 1943-44? What happens to the European Axis nations, are nukes used, are chemical/bio weapons used, and how badly does Japan get nuked when their turn comes? Would the IJA in mainland Asia hold out? Would Germany get permanently divided up and what does US society look like with much heavier losses and having permanent occupation duty on a large scale all over Europe, but then no Cold War?