I fixed it myself. Manually download the 1.0.13 version BIOS and flash it, then there appears a new option in BIOS which names "Intel multi-screen" (if my memory is correct). Just enable it and then reboot. The device manger shows two GPUs now. Both working with external displays.
Received my XPS 8950 a few days ago. I am very pleased with it overall. It’s a powerful, quiet PC. Specs: i9-12900K, RTX 3060 ti, 128 GB DDR5 ram, liquid cooling. The onboard Intel UHD Graphics is not enabled. It does not show up in BIOS or Device Manager. There is a DP and when I connected my monitor to that port, just to see if it was working, the error message said something to the effect of: “Onboard graphics have bee disabled on this PC. Power off and connect to discrete GPU” I have searched through all BIOS settings and there is no option to enable the onboard video. It’s not even listed. How do I enable the onboard Intel UHD Graphics? Onboard graphics would be required if I need to boot to safe mode for any reason.  Here is a photo of BIOS showing only the RTX 3060 as available. [IMAGE]      
XPS 8950, onboard Intel UHD Graphics is disabled