Playing a bit more, it looks like some outfits and Pokemon pull higher resolution textures with a negative LOD bias set. Someone smarter than I am could probably figure out a cheat to enable these without a driver-level setting. Who knows how it would run on an OG Switch though.
Also to clarify, this doesn't make EVERYTHING shiny and reflective; Pokemon and characters seem unaffected, stone pavers seem to vary between mid reflectivity and none, windows, cars, and water have very sharp reflections in them.
Not sure if this can be enabled with a cheat, but I discovered that using Nvidia Inspector's driver LOD Bias settings, you can get a bunch of reflections added into the game, so they must exist in the files somewhere.
Found with Ryubing 1.3.179 OpenGL mode.
See album for comparions:
So I didn't realize the 'Items Never Go Down' prevents you from getting new items, and now I'm missing some Mega Stones; anyone have a 'obtain all mega stones' cheat?