So for example the venu seems to support 24-bit color, while the Fenix 5x+ supports 6-bits (as far as I can tell, but I can't find it documented anywhere).
Screen width, height, and shape are all described in System.DeviceSettings. You can also get some display info from a Graphics.Dc (when you have one available). But I can't find anything that actually gives the color depth. I suppose some devices may not have an actual color depth, and could just have a color palette instead.
Is it something I just have to know for each supported device? And if so, is there documentation describing this for each device? Right now I'm drawing a color gradient in the simulator, and trying to eyeball how quantized it is, which is time consuming, probably inaccurate, and depends on the simulator getting it right...