Best case?
Hitler fears that Morale might be sagging so goes to the build up areas with Himmler, Gobbles and co, to inspire the troops. His plane crashes into a river and it's fuel tank catches fire, Hitler burns and drowns to death at the same time.
Germany collapses internaly 1943 and the allies make a landing in France and reach Berlin first.
Pre-Kursk was not too late for Germany to achieve some not all of its goals, with better leadership the war could end much later not earlier.
Think about this possible timeline. Those die who you say dies and there is no way in hell the Heer supports Goering after Stalingrad. The Field Marshal's will step in quickly and kill Goering, castrate the SS and end the Final Solution. You will have a military junta in place.
It depends on which generals/Field Marshal's are running things, but things for the Soviets will get alot worse militarily and for the Western Allies are going to get alot militarily and politically harder on the Western Allies as the loss of Hitler and Himmler with a regime that is talking the need for peace will make things harder to keep up the Europe first strategy and if Normandy fails I think Churchill goes down as PM perhaps replaced by Lord Halifax and FDR goes down in the November elections in favor of a Dewey who will be talking peace with honor with Germany and a focus on the enemy who attacked us.
I honestly think a peace between the U.S., UK and Germany is hammered out handing over France and the Low countries by early 1945. I suspect Dewey kills Lend Lease to the Soviets, but not the UK as long as they are still in the war against Japan which they will be.
With international markets open, Germany not having to have tons of forces in the West, with Germany not having to deal with Anglo-American air attacks and without Lend Lease to the Soviets it will be a whole different ball game. The war in the East grinds to an end by 1946 or 1947 at the latest. I expect something akin to the 1940 borders would end up being where the line gets drawn.