Very very strange…
There’s 2 EFI drivers for video, the one from Intel onboard on the main bios and the one from your 3080Ti on the vbios of it.
What’s model of that OLed display, connected via DP? no support/firmware for it?
The system always boots from dGPU and older to newer port, by default.
UBU for onboard EFI GOP, GOP Update and Extraction Tool (Turing) for the 3080Ti…at your own risk of course…
Odd as it happens in 2 different LCD models…same cable?