I've also investigated this quite deeply. As I'm sure most of us know, the main problems with 'webcams', either the built-in ones or USB ones that you perch on top of your monitor, are the lens size, and the CCD/CMOS image sensor size. Manufacturers spouting specs like '4k' are deliberately misleading the public if the sensor and/or the lens aren't also upgraded. The only cost-viable methods to get 'broadcast quality…
I vaguely remember reading about a video card that had more RAM than it was able to address.