Doesn’t work. Not a Linux issue. No graphics card or motherboard maker connects the hardware correctly to support CEC on PCs. It’s an industry-wide practice.

There is the pulse eight injector which together with software can inject CEC with a USB connection with the caveat it can’t turn your computer on and it’s a hacky and imperfect solution for tinkerers rather than production ready equipment. Also it’s only HDMI 2.0 not 2.1.

Actually the shutdown bug was part of a security patch and I can confirm it affects Windows 10 machines with ESU.