I have the 27" from that series. In my experience, after I fixed the RGB issue, I also fixed the flickering issue. And to fix the RGB issue, I used BetterDisplay[1], controlled by a Hammerspoon[2] script[3] that calls its CLI on the appropriate display events.

The free version of BetterDisplay is sufficient, I really don't use any of its other features.

The flickering seems to be gamma related, and is triggered by Nightshift or Flux for me.

[1] https://github.com/waydabber/BetterDisplay#readme

[2] https://www.hammerspoon.org/

[3] https://github.com/wlonkly/dotfiles/blob/master/home/.hammer...