I have one last question for you guys who have the 32in (U3223QE)
I just want to see if it's really my monitor that has a problem.
You can test it on any ports, USB-C, HDMI or DP (problems occurs on all of them). Now I would like you to enable HDR in the monitor settings (any of the HDR modes), then in macOS or windows DON'T enable HDR.
So you enable support for HDR but you don't enable it on your computer. Now try the presets. In my case, Game and Movies modes are all messed up. It seems that the monitor is forcing HDR on these exact 2 presets even if the computer hasn't enable it. All other presets, Standard, RGB, etc should work fine.
I also have the 27in version (U2723QE) and this works as it should
thanks for your help!
tl;dr :
1- enable HDR in monitor
2- Don't enable HDR in macOS or windows
3- Try preset Game or Movie and check is colors are all messed up