Implement wp-color-management
The wp-color-mangement protocol allows the compositor to tell clients what color properties (wide-gamut, etc.) are available on outputs, and for clients to tell the compositor the color properties of their surfaces. It enables things like HDR graphics/video, and also allows for accurate color reproduction, which is a basic requirement for professional (and even often hobbyist!) photo and video production work.
However, the protocol requires decent understanding of color management and the science around it, so it is probably not trivial to implement. In addition, smithay requires rendering pipeline changes before this protocol can be truly supported and useful. There might be some things we can do to at least support one basic thing, HDR video, but it would still require a bit of work, and someone with graphics knowledge to implement (and a monitor that supports HDR to test it!).