Dehaze True Manual Color Selection

Hi ! I've recently started using the dehaze tool as a way to control contrast in a more fine tuned way, especially by adding haze and then tweaking the contrast slider and curves to bring back contrast. I believe Dehaze behaves differently than the Contrast Slider correct?

The issue is consistency ! It's impossible to select a fixed color ! (In my case I want pure white or gray haze with no color cast) I can sometimes color pick white or gray on certain images but on images where white is not available in the frame it doesn't work... and color picking on one image (with a color checker for example) and then copy pasting the layer on another image, a new color is automatically calculated, even when MANUAL selection is selected in the drop down menu.

This creates inconsistencies in my workflow having to constantly adjust and correct the tones of my contrast layer for every image instead of having a reliable contrast layer i can paste onto any photo...

The current dehaze tool works great as is but being able to truly manually select a color (and keep that same color fixed) would open more possibilities for grading images !