You are pretty much correct with everything you said, however even the obsolete Pz38’s would have wrecked havoc upon the mechanized infantry, trucks, halftracks, and logistical units accompanying the Soviet tanks. Plus the tanks were heavily dug in and concealed which would have made fighting them harder.

The real risk the 22nd posed was holding up the Soviet advance just long enough for the modern and more dangerous panzer units in Stalingrad, and rear line reserve, to mobilize and prevent an encirclement. A problem that thankfully was not encountered due to the help of some cold field mice.