Sure, you just use OpenGL or Vulkan and don't bother with UWP. You're shipping games on Steam anyway not the Microsoft Store. If for some weird reason you care

Sure, you just use OpenGL or Vulkan and don't bother with UWP. You're shipping games on Steam anyway not the Microsoft Store. If for some weird reason you care about Windows Mobile then UWP still isn't useful because it doesn't support Windows Phone 8, which is the majority of the windows mobile marketshare.