“My central point is to show that the outcome could have been different in many, many ways, up until the breakout from Normandy.”
Actually, the fate of Germany was sealed before that, in frozen Stalingrad. The losses there were huge, and simply could not be replaced. Of more importance than that, was the effect it had on the German Allies, Hungary, Romania, and Italy.
The losses among the allied forces at Stalingrad represented almost the whole of Hungary and Romania’s militaries. the losses in men and material simply could not be replaced.
The Italian losses, which were pretty much everything and everyone they sent to Russia, were politically devastating for Mussolini.
The wipeout of the Southern Front, with no reserves available to stabilize it, before it became a rout, forced the withdrawal from the Caucuses, where the Germans were within eyesight of the Oil derricks, and the Caspian Sea.
Had the Germans withdrawn from Stalingrad before it became a quagmire, and consolidated, they may well have had the reserves to not only prevent Uranus, but to consolidate the Caucuses, and keep the allies in the war.
I think your timeline is wrong. This exercies begins Dec 8 1941. STalingrad had not been attacked, yet alone repelled, at that point. The entire battle of Stalingrad does not happen under this scenario.
Although lost their Army group, but it was still recoverable, as Mannstein was able to provide some stability. Else they would not have later gone on the offensive at Kursk.