cool down, collegues.
I also had been in contact with a neutral BMW car expert meanwhile, and he strongly adviced to have the oil refilled in the BMW dealership. So I had the car moved to the BMW Center close to my home today, and they promised to refill the automatic gearbox by tomorrow.
This will end in a quite shocking invoice, but destroying the gearbox would be even more expensive. So I won't take any risk on this story.
Greetings
Thomas