You can get light or dark variant of a color declared in assets automatically in SwiftUI by switching on your phone theme. If you choose the dark mode on your phone, the color appearance will be Dark Appearance, if Light, then Light Appearance.
If you want to use a whiteboard on your meeting or annotations, there are a couple of steps to pay attention to. In this video, I want to break down how to use Whiteboards in zoom as well as how to use Annotations in zoom.