In the film editing space workstations use dedicated video I/O hardware which fully circumvents the display/video stack of the OS to be able to input/output exactly the pixels you want in exactly the format you want (something that's essentially impossible using OS facilities, much less in a cross-platform manner). This seems like a very good application for those cards (they're not particularly expensive, around 200 bucks [1]).
[1] https://www.blackmagicdesign.com/products/decklink/techspecs... (4K, PCIe) https://www.blackmagicdesign.com/products/ultrastudio/techsp... (less than 100 bucks, but only 1080p on Thunderbolt) (SDK: https://www.blackmagicdesign.com/developer/product/capture-a...)