How do I set up a material for a skydome that is just directly visible but does not contribute any lighting to the scene and does not receive any lighting but acts as a backdrop to the environment?
Corona renderer in 3dsmax used to have something similar where you can have a directly visible hdr image but it does not have any lighting effect on the environment. You could also make it visible for reflections in the scene too.
I have turned off cast shadows for the skydome mesh but Lumen is still casting shadows from the sphere.