Editing this to say PNG worked better to reduce the artifacts. Color is just borked by the game's post processing, I tried every LUT I had but nothing looked normal. So, I desaturated the grey all the way (originally it had a touch of orange for warmth) because the game overexposes and saturates every color like it's a Lisa Frank fever dream. I ended up taking all the colors down in brightness and saturation a by about ~40% to counteract how "hot" they come out in game. It helped a bit, but I still can't get the shading to look right in game. It washes out every time. Making it darker in my image editor results in a harsh black mark in game, not a smooth gradient... Oh well. Hopefully this helps some other newbie trying to texture their shiznazzle. Rock on comrades.