Help with new Monitor

[Mark7]

Hello,
I’m having issues setting up my new monitor and I can’t figure out what’s wrong.

I recorded two videos to show the problem:

• In the first one, the text changes color while scrolling: on red background text goes reddish/pink (same effect on blue) in any browser
• In the second one, the text becomes blurrier/thinner when moving in‑game.

I don’t understand what’s causing this. The issue appears when I connect the monitor (Q27G3XMN) to my new PC (9800X3D + 9070XT), but it does not happen when I plug the same monitor into an old, cheap Intel + Nvidia laptop.

Here’s what I’ve already tried:

Uninstalled and reinstalled GPU drivers using DDU

Turned everything OFF in AMD Adrenalin

Verified that resolution and refresh rate are correct on both Windows and the monitor (1440p / 180 Hz)

Swapped GPU ports and changed the cable

Tried HDMI instead of DisplayPort

Disabled Night Light and VRR in Windows 11

At this point I’m out of ideas. What could be causing this?
Thank you all for your time