also some buildings will look bad with snow inside or below the roof, what you can try to do is make a copy of the buildings, on original you delete the floor out of the nif file with Nifskope, on the copy you delete everything else out of the nif file except for the floor, that way you have 2 building pieces and you can apply different snow settings to both of them in the creation kit. you can also change in the CK the 'max angle' in the building object settings to apply less or more snow. nif file and then the game will apply this new snow on its roof, however, some objects need this NiAlphaProperty, ive noticed myself if I remove this on some buildings in order to get snow on them I get black areas instead, so it seems I'm forced to choose between either having no snow, or having black areas on some objects. some objects will work fine with just this, however other objects will not because if you open them in nifskope u will see they have a 'NiAlphaProperty', so lets say you want to use the new snow that uses the new SnowShader.nif on a farm building, well it simply wont work unless you delete the NiAlphaProperty out of the farm. nif file, also disable the 'single pass' option.

duplicate a snow material in CK (like SnowMaterialFarm for example) and point it to the new. use the new 'SnowShader.nif' from the mod Better Dynamic Snow. So now its up to me to patch out all of this and apply the settings from 'better dynamic snow' onto these new objecs, just in case anyone else lands on this topic through google, here is how I'm doing it: I came here from google and it really helped me to figure out how this snow worked, I too had extremely white snow on things like walkways and some houses, all because those were added by mods that had their own snow applied to them, meaning the mod 'better dynamic snow' did not affect the snow since it were new objects.

Skyrim se snow shader