I'm not sure if this is a bug, oversight, missing feature, or I just can't find a way to do it but I need to change my workspace color to something much darker. I can set a UI preferences to a dark theme and that's a big start but the document color, even when set to transparent is still white (light grey checker is still very bright). This actually increases eye strain against the dark background & UI. My expectation would be that the shades of the transparent document space shift with the light/dark theme and background or artboard sliders.
Dragging a rectangle over every page isn't a viable option for publisher and and even in designer creates other issues since I want the "blank" space when time to export out transparent images or for printing without having to find and disable every cover-up cludge. This is an accessibility issue for me (and long term eye health for everyone) but applies to general industry of printing to color or non-bleached stock or anyone that works in teams and one may prefer dark screens and another bright.