What if the top ranking Nazis had realized (as surely some of them did) that the war was going south earlier than our TL, say 1943, and (rightly) decided the only way they were going to get out of this intact was by immediately halting the mass extermination and covering up all evidence it ever happened.
If they had started in spring 1943, could they have successfully hidden all evidence of the Holocaust?
If so, how would the world look back on the Third Reich?, would antisemitism be more widespread due to lack of guilt over the Holocaust?
EDIT:Hitler has been deposed, January 1943.