WeinTrust That is interesting. Did you try raising contrast to 125 instead of vivid colors? I think has a very similar effect without the oversaturation. Raising contrast in the display driver is somehow different than raising it on your monitor, whites will be crushed, but i have seen some people do it on purpose. Not sure i like it, but perhaps it helps.
I dont use brightness 0. I use contrast 0 and adjust only brightness to 35 on my benq and 65 on my eizo(this is darker than the benq). If you have a problem with peak brightness try this.
What helped me was deinstalling adrenalin drivers and taking AMD Pro drivers. Text is very clear and sharp with that driver. Gaming perfomance is the same i think.
I get more Eyepain, with too much green in my white point(for example Benq monitor R/G/B=97/87/94 is much better for me, than perfect white). Dont know why, tried it with various monitors. And RGB limited on monitor and display drivers is essential to make HDR watchable.