I was thinking of having the Germans adopt a defense-in-depth strategy after Hitler's overthrow in this scenario and aggressively and quickly build as many defensive lines as possible on all fronts. Think of the 1917 Hindenburg Line or the defense-in-depth at Kursk, but on a much, much larger scale. Anyway, how successful do you think that such a German strategy is actually going to be and just how much bloodier are the final year or two of World War II going to be for the Allies in this scenario?
The best Germany could had done was to sue for peace in mid 1943. At that point it was clear things were going south. Concentrate large troops, fake commitment to long war, sue for peace, and try to give and get with the Soviets. Tough to do after they already broke an agreement in 1941, but nonetheless at that point in mid 1943 was the last chance to gain something reasonably through negotiations.
Which is probably why military tried to dethrone him, to get fresh leadership for negotiations. Good thinking but didn't work.