Stalingrad was Case Blue, and the initial objective was to take the Caucasus oil fields. The Battle of Stalingrad was stumbled into. And the Germans were at the end of a 1500 mile supply line. Hitler was warned they could be cut off and surrounded. He ignored those warnings. Paulus was only promoted Field Marshal near the end. Hitler expected him to kill himself. Instead he lived to a ripe old age in what became East Germanny (the DDR).
If Hitler had bypassed and cut off Stalingrad initially, he might have won the war. I have heard that he was obsessed with taking the city carrying the name of his enemy. It sounds like the sort of thing that megalomaniac would do.
“Stalingrad was Case Blue....”
Yup. Hitler’s plan was to take the Russian oil fields in the Caucasus, especially those at Baku; and in order to isolate that objective the German strategy was to use Army Group South to eliminate the Soviet threat in the Crimea and the Soviet forces between the Donets and the Don, west of Stalingrad. The initial plan for Stalingrad was not to attack and destroy it but to cut it off and neutralize its industrial and communications assets. As you know, things quickly spiraled out of control.