We are not aware of any issues with the ML series generally, but big wheels and low profile tyres like those fitted to your car are more sensitive to the camber on the road and that could be your problem. As you've already had some success in getting action from your dealer I would suggest you head back there and discuss with them what they might be able to do to improve it even more.

You would expect the revs to increase when you downshift to a lower gear whether the cruise is on or not. It’s normal for the cruise to stay on unless you hit the brakes or turn it off using the switch. You can overtake by using the wand on the steering column to increase your speed and then use it again to decrease it once you’ve overtaken and it will then resume the previously set speed. You could also just use the accelerator to increase your speed and then lift off once you’ve overtaken the other vehicle and it will again come back to the set speed.

The rate of depreciation will be the same as any other Mercedes-Benz model; while the AMG badge will be more attractive to buyers it won’t slow the rate of depreciation as it might once have done when it was a rare model. Unfortunately your car was immediately devalued when the new price was cut with the tariff reduction, there’s not much you can do about that.