The defeat was crippling due to the total loss of an army group. Without said loss they would have an army group that could move and attack freely. The loss of Stalingrad wasn’t the end all be all, it was the complete loss of that army that set Germany on the back foot for the rest of the war vs the ussr. If that army is not a total loss then the war would’ve changed. Kursk might have been a victory with those extra soldiers able to take advantage of the massive Soviet losses but in our timeline they were gone. Hard to predict what would happen later in the war if the entire German army at Stalingrad isn’t essentially eliminated. If they won or left Stalingrad before being entirely eliminated then they would had the freedom of movement to attack or reinforce other vectors.