[Karaya]

All AP shells above 20mm in the german armed forces have an explosive filling.
Only some shells (ex. AP40, tungsten core, sub caliber ) don't have explosive fillings.
And i bet my shiny metal ass that the shells used in the stuka are normal AP shells.
So what you see in the original videos is correct (logical) and what we have in IL2 is incorrect.

The Stuka G-1/G-2 Kanonenvogel used Tungsten core AP shells for anti-tank purposes, so no HE content there!

In the video HE shells are probably used which were also available to the BK3.7 cannon, we have that kind of ammo in a mixed belting on all other aircraft that are capable of using that cannon ingame (Bf110, Hs129)

The BK 3,7 was used successfully against tanks, most notably by the Ju 87G, firing a 405 g Hartkernmunition with a tungsten core at 1140 m/s. It was also tried in the air as a weapon against heavy bombers, in Bf 110s. The conventional APHE (680 g) and HE (640 g) munition was used. It was not successful in this role.