What shoes to drive?

For truck drivers it is probably prescribed and also makes sense with dirty soles, pedals and footroom: The “fixed shoes” with anti-slip sole. But what does this look like in the car? I like to ride without shoes on longer rides (these lie in the unused passenger footroom (birkenstocks or half shoes with leather soles) or in the trunk (work shoes)). On the one hand, the clutch point in the 2111 Lada is similar to the Audi A4 of a colleague “right far up” (should probably be more sporty). If I switch from the diesel engine on to the petrol engine on a working day, it will always take me a long time to get used to the changed starting behaviour (the engine is far too quiet and at the traffic light it will drain off with false domes – even after 16Tkm with the car), on the other hand it is simply more comfortable without shoes. Now my question: Are there regulations about whether you have to wear shoes for private car driving? do not rationally understand on street shoes, since the human foot sole (without stockings) is already ideally anti-slip in the OEM bio version, but the leather sole of the street shoe can slip off the pedals in an unfavorable case.