Brand new $2600 Surface Book 3 on a Surface Dock with a Dell U4320q over DisplayPort and the same 640x480 nonsense. I plug in my Surface Book 2 into the same exact setup and it is fine. From everything I am reading it is clearly something with the dock and Intel Iris graphics. Incredibly frustrating for such expensive hardware.
This was a POC for further corporate investment due to COVID and this has us looking elsewhere.
You folks need to allow roll backs of the firmware if it isn't impactful.