> automatic dimming features don't work well up here

That's disappointing to hear, but a counterpoint: the first car I ever drove that had auto-dimming was a Ford Escape rental in Utah. I drove from SLC to Moab and back, plenty of night driving in mountains, and it performed far beyond my expectations. I really never had to adjust the lights manually.

Which is to say, probably more to do with the specific implementation than the terrain.