BMW 650i total engine damage

Hello, it is about a BMW 650i 2012 with 87500km. The car is moved last months in the city. Yesterday I went on the highway, on the return drive at the acceleration track full throttle, then came a loud bang, and white smoke behind the car. Forcibly stopped, I had 15 oil track and the whole oil ran out. From the engine compartment even a metal piece fell. I had directly in front of it no lamp on, at the drive I drove 120-140-150 km/h over 14 km, the engine was warm. After an acceleration at the traffic lights, he had run out of time in the city and then ran in a very restless position. After 2-3 hours everything was ok. He actually ran very well and also no oil consumption. I know, actually it doesn’t matter now. It just happened, the engine is history. You still deal with why question, probably for processing. Here comes my question. Is the repair or with engine damage so worthwhile? Are there in Ruhr area experts ? Where do you get a reasonable AT engine with warranty and of course costs. What is your experience? Thank you