Some games cannot go fullscreen

[Bo$s]

Recently I bought Dell D6000 and I'm facing a strange issue where one of my games, Counter-Strike: Global Offensive can't go fullscreen on display connected to this dock.

My setup is as follows:

• Inspiron 7577 gaming with second GPU (GTX 1060 MAX-Q)
• Windows 10 Home 1909 with latest updates
• Nvidia drivers 445.87
• Dell D6000 with A03 FW connected via USB-C
• DisplayLink drivers 9.3.3147.0
• AOC 2260 connected via HDMI to D6000

The issue is that when Windows is configured to use external display only, then after starting CS:GO the desktop screen "freezes", however, I hear that game starts and it's running but no UI is displayed (I can also hear menu sounds when I'm moving the pointer). Also, according to the Task Manager, main GPU is used to render the game UI. I still can use Alt+Tab to "unfreeze" the screen, however, when I focus back the CS:GO process then screen freezes. The same issue occurs when Windows is configured to extend displays and the external display is set as the main display.

The interesting observations are:

• Game is correctly rendered on both displays when Windows is configured to duplicate the displays which to me proofs that game can be rendered on the external display
• Game starts correctly in Windowed or Fullscreen Windowed mode (however, performance and overall experience is quite bad) so that's not an option)
• Game works fine when the external display is connected directly to the notebook

So far I tried to:

• change CS:GO launch options, no luck with different setups here
• downgrade to 9.1 drivers as such version is offered by Dell
• updating DirectX runtime libraries
• Resetting Windows

I'm really happy to get some help here, workaround ideas, or anything which would help me to solve that issue.