Let me answer the OP realistically.
There is really only one possible scenario where Germany wins Stalingrad--Hitler does not change the Case Blue plans before the dash to the Caucasus mountains on July 23, 1942. It is possible that without this change, Stalingrad would have fallen on the march within a week.
With such a POD, the German attack grinds down somewhere just east of Grozny. Baku won't be taken.
Germany will have much better defensive positions and would like do better taking some of the port towns on the east side of the Black Sea.
The USSR, in this event, will not be able to successfully dislodge the Germans from Stalingrad or envelop AGS in the winter of 42-43. AGC and AGN have roughly similar performances ITTL.
After this the PODs get so divergent that it is hard to guess. The Wallies might change strategy fearing that Russia is "collapsing" (though in reality Russia would still have a very strong 43). Pretty much everything hinges upon what the Wallies do:
If the Wallies attack France in 1943, the USSR by the end of the year forces a German withdrawal from Stalingrad, Grozny, and Maikop. Germany will hold onto Kerch and Rostov. They will withdraw from Rhzev due to manpower shortages and the need to deal with the Wallies. The USSR will be spent in this scenerio, now facing manpower shortages (they have not liberated enough land ITTL to make due on manpower losses, plus the loss of fuel hurts agriculture and their ability to conduct mobile warfare.) The Wallies IMHO (I know Wiking disagrees) get their rear ends handed to them in France, because IOTL this almost happened in Italy...twice (in Salerno and then Anzio). In France, Germany will have a strong Luftwaffe presence and many more men. All in all, the end result is probably an armistice in the east that grants Germany all of Ukraine, Belarus, and the Baltic states. The Wallies like continue the war anyway through a blockade and strategic bombing, still demanding France's independence. The result is that Germany gets nuked and the Wallies pretty much control the post-war world.
If the Wallies focus on knocking Italy out of the war, the USSR probably still liberates Stalingrad, Grozny, and Maikop. Germany does not withdraw from Rhzev and the USSR is spent economically and demographically. They do not make a peace, as the Wallies are still "in the fight." However, the USSR plays defense. By the time the Wallies land in France in 44, Germany starts collapsing precipitously. The Wallies and Soviets meet in East Prussia in August 1945. The Wallies end up experiencing hundreds of thousands of more casualties. WW2 is a bloodier affair for the Wallies, depending upon how they maneuver this may increase or decrease the prestige of generals such as Patton, Montgomery, etc.