I have discovered two solutions so far.
1. Kernel with screen options (let's you change color values - depends on the phone tho) 2. Screen Adjuster :
https://play.google.com/store/apps/details?id=com.netmanslab.sa - Bug : you have to disable screen Adjuster if you want to install an app manually, check the description.
I also prefer this one but I'm fine with those 2 as workaround.
Yes but there are two problems with these apps. First they ONLY add tint.. you cant subtract a color, just add more color.. that destroys the Gamma curve and add a haze/tint to the whole screen (specially visible on dark areas).. it looks just as bad as not not trying to correct the colors. Would be simple I think for the developers to modify the sliders to - and + / +100 -100% instead of just 0-100%.
But the second problem is that these apps destroy the GUI performance! All gets slow, stutters, lags and all animations and flow of the Tab becomes a disaster! Cant use. Unless the developers of these apps fix the problem, these apps really are no good. I wrote to them before and made a request but got (as usual) no reply.
And as for the bug of having disable the screen adjustment to install an app, yes, I know and its also silly but not a huge issue for me.. surely the developers could also fix it..
So really, Im still looking for a proper solution.. these apps are not a solution and do more harm than good.. add horrible tinting when changing colors, kill the desktop performance of the phone and interfere with app install.. lots of issues and still not get acceptable color correction!