How is your phone doing on your snow photos? Have you made any? If you have, does the snow look gray?
If it does, here’s an old photographer’s trick. If you phone will do it, increase your exposure compensation by a half stop or two-thirds of a stop.
That’s because all cameras, phone cameras, too, try to achieve an exposure akin to 18% gray. Most of the time, that’s perfect. But on a specialized situation, like where everything should be white, you have to tell your camera to lighten the snow to white. Shoot it a few times to make sure the snow is white, but not blown out white.
It should fix gray snow pictures. Good luck.