Intel-based 2019 iMac 27" Retina display not detected / not working

I have a 27" Retina 2019 iMac that I purchased recently. The internal monitor remains black and is not detected within system settings, however external monitors attached via the USB 3 ports or even wirelessly work just fine.

I went ahead and purchased a new replacement monitor for it and even with the new monitor, no response and it remains undetected by the operating system. Is there a bios setting that could have failed? I've also opened the iMac, checked the connectors with a low-level microscope to see if there were any pins missing, but the connectors look fine as well.

I don't see any damage or fried circuits on the motherboard either. Has anyone else experienced this issue and, if so, what did you do to resolve it?