The secondary color corrector fx is kind of like a chroma key, but instead of removing an isolated color range you can change its hue and saturation. I used it extensively in my Coaxium Heist edit. I picked a screenshot that has greenish/blue darks, selected that color range then brought the saturation down to around 0.4 for that specific color range. The result is a slight adjustment of the greenish blue to more of a grey which looks more accurate (to my eyes) for things like steel and imperial uniforms. I was able to do a mass apply to the whole film as it has this issue generally. I found a color corrector low/mid/high wheel did too much to the overall color so I went this route. I should look into LUTs again. Im kind of picky and never really fully agreed with any LUT I’ve used in the past.