If you want to you can do that right now. It’s kinda possible. I started doing this in Blender, Affinity Designer and works if you have the Zoom to Feature on the 3d program.
Math will be different for other monitors but this will work if you have a standard 27in Monitor on the Mac.
Go to Full Screen mode (this works if you set the display at 2560x1440) and make a sketch square 7.7inch and zoom to (the Space button) the sketch. Go to Appearances and save the view, if you are in Perspective change to ORTHO.
I’ll probably try this on the iPad too will report the dimension when I find out.