So, say that the most competent German commandes had been given free hands just before the allied landings in Normandy and Operation Bagration. Probably ASB, but say that Hitler is uncapacitated by a stroke induced by his heavy drug use and a troika mostly of army men take over.
How long can the Reich survive? Can Finland be kept in the war longer? Can the Russians be held outside Romania for some time, giving Germany more oil? Would not getting troops surrounded in the Kurland and Ostpreußen pockets allow the Germans to hold the Oder line for some time? Especially if the forces sent to the Ardennes offensive is used in the east instead?