I think Stalingrad showed that the Russians were just too powerful for the Germans.
The Russians had terrible losses but they could afford them.
“Barbarians at the gate” was a great movie about Stalingrad. Centered around two opposing snipers. But had some scenes of Russian charges that , if true, were pretty amazing. Not enough weapons for the troops so they went in teams of two soldiers and when the lead guy with the rifle got shot the guy hanging on to his belt picked it up and continued forward. Anyone who turned around in retreat was shot by Russian troops.