Have you checked to see if the rear headlight level is in the correct orientation? If you pulled down the control arm far enough, the headlight level can switch orientations (think an elbow bending in the wrong direction). If this occurred, it will sound like the rear suspension is making a lot of noise. Perhaps check that out since it's an easy check.
It's items #1 and #8 in this diagram.
https://www.realoem.com/bmw/enUS/sho...diagId=33_1819