In reality, armor often suffered from bad quality to the point where the Germans still could penetrate the armor because the armor couldn’t hold, slopped armor has the disadvantage that it makes the interiors smaller, makes the crew easier to kill, most tanks had no radios, only four crew members/ overtasked commander and gunner, awful suspension (system) and in general next to no crew comfort. Not to mention that the crew were mostly recruits who lacked training.
Iiirc most confirmed destroyed, knocked out or disabled T-34s in the first winters were caused by Panzer IIIs (Around 50%).
Better reliability (that was before they turned mad and created technological abominations), more experienced crews, partly better logistics in the first phase, and better research, and also the Soviets in general suffered from shocked and undermanned leadership and lack of communication.