Update: I replaced the 2018 Alante 31R factory bulbs with Sealight S6 H11/H9/H8 LED bulbs and H11 9005 LED bulbs (from Amazon) with very favorable results. Also, after installing the the bulbs, I realigned the lights.
The difference was night and day! (Yeah, I said that.)
Big improvement, due mostly to brighter light, but the realignment was needed to. Perhaps the halogen bulbs were tired after four years, but I don't remember the night visibility ever being as good as it is now.
By the way, I figured that the headlight assemblies are derived from a 2008-2015 Chevrolet Silverado. This is good to know if you are looking to replace the housings or want to identify compatible bulbs.