Good points - so you're in the 1 September 1939 camp, then? I've sometimes thought along similar lines, namely that getting into a war with Britain and France was a major failure of foreign policy, especially as it was a war which Germany did not have the ability to win. There was no prospect of defeating Britain outright, because Germany lacked the naval strength to invade. The defeat of France was incredibly lucky and it obscures the fact that Germany was now in a dangerous war with the British Empire which was like a festering sore that would always come back to damage Germany at every opportunity.
Imo the decision to invade the USSR while Britain was still in the war was a mistake. It was a reckless gamble and it should never have been taken; focusing on the Mediterranean and Midlde Eastern theaters of operations to end the war with Britain would have been the correct move. A German statesman of greater foresight and ability would have recognised this. It's difficult to imagine someone of Bismark's stature making the same mistake. A scenario where Germany adopts a "Britain first" strategy and concludes some sort of peace in say 1941 or 1942, perhaps following victory in the Mediterranean/Egypt, would have reset the clock and allowed a halt to the escalation before it was too late.
If the invasion of the Soviet Union still goes ahead then, there will be no British and American supplies to the Soviets, no trucks, tanks and planes, no boots, no food and no fuel from the Allies. There will also be no distracting theatres of war bleeding away the Luftwaffe's strength and no need to garrison the west with substantial manpower. The outcome then might be hard to predict. Treating the Ukrainians and other subject peoples of the Soviet Empire well and winning them over with support, rights, self-determination and friendship as part of a liberation effort would have been an incredibly smart move, too. The Axis forces were initially greeted as liberators by these people and if the right approach had been taken, their help could have been enlisted to free a large part of the Soviet Union willingly. This would have achieved the primary war aim, to defeat the Soviet state, and would have created new German allies that were very favourably disposed to Germany. It would have been an eminently sensible policy. But of course, the Hitlerists lacked the wisdom to see that.