Precision 7750 slow UI performance while using both external and internal monitor

Greetings,

Received my new Precision 7750 workstation yesterday, it's all updated to latest versions, here're the specs:

• BIOS 1.6.2
• Windows 10 Pro 20H2 19042.804
• Intel UHD Graphics driver 27.20.100.9168
• Nvidia Quadro RTX 4000 driver 27.21.14.6140
• 4k HDR 10 bit 17 inches display
• 4k SDR 8 bit sRGB external monitor AOC U3277PWQU / HDMI 2.0
• i9-10885H
• RAM 2x16 GB 3200 MHz
• Storage KXG60PNV 1 TB

My problem is the general UI is slow and stutters when I use the internal monitor and even more when I use both the internal and external monitor at the same time. UI movement, desktop transitions, everything has non-60 Hz framerate, very noticeable during 4k video playback.

Also the internal display just goes full back and never goes back on when I switch off HDR in Windows HD color settings (event after restart the system), can only get it back if using another monitor I set HDR back on for the internal display.

When I use only the external monitor, the experience is as it should be, very smooth and responsive, 4k video playback is perfect.

Here's what I tried so far:

• In Nvidia control panel, setting preferred device as the Nvidia GPU, and checking if apps like Chrome are set to use it => not fixed
• In Windows graphic settings enabled Hardware-accelerated GPU scheduling => not fixed
• Disabled the Intel HD driver in device manager > performance seems better but not much and I loose brightness control on the display, internal monitor was set to "generic display", didn't help
• Tried updating the Nvidia and Intel graphic drivers from different sources, but the behavior remains the same

I usually work with both built in display and external monitor, by the looks of it it's as is the Intel GPU wasn't strong enough to simply handle the built in 4k resolution smoothly? Event using the internal display only it's still noticeably slow, the experience is only correct when using only the external display that is handled by the Nvidia card..

Any idea? I though a laptop with that strong hardware wouldn't struggle with simply using its built in display and push me to use only external monitors..

Cheers