I had tried the way to use exponential height fog(fog height = 0, set up color) and post process volume and Directional light (uncheck Atmosphere Sun Light) and Atmospheric Fog(uncheck Use Attach Parent Bound)
Have you tried adding post process volume → Unbound-> Make the exposure Min EV100 and Max EV100 to the same number? It will turn off the eye adaption in UE5 so the light would not affect by the camera and where the viewer is.