Hi Thorben,
I don't know the answer to your question. But, I do have a comment that might possibly be of use to you.
When preparing to order my EQE SUV here in Sweden, I looked at an EQC in the showroom, as the dealer told me it was very roughly the same size/style as the EQE SUV. I wanted to get an idea of what it was like to sit in a mid-sized SUV, as I have never owned one before. I also wanted to know more about the running boards, which this EQC had. I found that even though the car was an SUV, it was still low enough to enter easily, without using the running board (I am 177 cm). Using the running board to enter was also possible. BUT...here is the surprise... the ergonomics for exiting the vehicle are simply BAD. The running board is not "deep" enough for you to use it as a step to exit the vehicle, thus you must have your foot parallel to the vehicle, which simply doesn't work. So, to exit, you need to bypass running board and step directly to the ground...but this is made very difficult by the existence of the running board. You have to move your leg way away from the car to clear the running board. You will also drag your pants along the (probably dirty) edge of the running board.
I realize you're looking at an EQS and not an EQE... but I expect the situation would probably be the same. You really want to try this out in a showroom somewhere, before you buy the running boards!