We have a 2020 29M and it had a wind/speed related buzzing under the dash. Very difficult to pinpoint precisely but it only started buzzing at 40-45 mph, regardless of engine rpm. Our dealership spent a lot of time taping, insulating, plugging various things under the dash in the engine compartment. This reduced it to a tolerable level but it is still there if you listen closely. They never did find the source of the buzzing, only reduced the noise. I plan to remove as much of the inside dash panels as I can and do more insulation and taping under there in an effort to reduce not only the buzzing but all the other wind/road noise.
I like to travel, but I also like to get back home.