BMW 1er Turbocharger Damage

Hello, I need an expert assessment from you, it’s all about the following:We have a BMW 1er, built in 2018, mileage approx. 96000. The car is affected by several recall actions, including those of the AGR cooler. After the part of BMW was ordered and could not be delivered, it bursted on the highway and also damaged further hoses, the engine was ruined, etc. The costs for the repair were taken over by BMW. Now we have remained on the motorway again on the way to Austria, because we noticed a buzzing noise during the ride. This was not there right after the engine started again. We were towed away from the ADAC to BMW and there we were told that the turbocharger had to be replaced completely and the costs will amount to 4000€. The question whether it is related to the bursted AGR cooler and the further damage is related to it, was immediately negated and not further examined. After further research, however, our assumption that it is more and more connected. How can you see that?