I love the 6 cylinder but unfortunately today the offer is very limited.
In the 4 cylinder there is a better weight distribution (engine weight closer to the center of gravity) and up to a few years ago also a higher torque in the lower part.
In the event of a frontal collision, the small size of the 4 cylinder has an advantage. In EUROENCAP tests, a small engine is preferred for better results.
I say long life to the BMW 6 cylinder