What I've heard, for some reason, you can get CEC and working when you use a displayport -> hdmi adapter with the right chipset inside. So theoretically, get the right adapter, plug it on the side of the computer and you might actually get CEC signal decoded as a new kernel device.
Are we talking about the same Windows operating system? The one I know is definitely not well documented at all. The "fixes" in the official Microsoft forums/support pages are usually to either run sfc /scannow or to reinstall the whole OS. When community comes up with some registry based solution, it either doesn't properly solve the problem or reverts back after the next update/reboot.
I'd say the problematic part is not capturing the desktop but injecting controls into it. Proper universal support for simulated input is still missing.
I thought they actually dumbed down the model names. Basically the more adjactives the laptop has, the higher the model is. Now the machines can have pronounciable names and just add generation number every year or so.
Sure, the original numbering system did make sense, but you had to Google what the system meant. Now, it's kind of intuitive, even though the it's just a different permutation of the same words?
Would it be enough to have <body> hidden using an inline style in the initial html response and when everything is loaded, one would remove the style using javascript?
Well, yes, but APIs aside, as long as the developers and users have the choice, they won't choose a new backwards incompatible solution if when they can stay with their old solution.
Look at Apple Macs, all went from x86 to arm, breaking software and fixing incompatibilities later. Users had no choice but to use m1 macOS if they wanted a new device.
That's a reasonable baseline, yes. I would also consider trying running it on Arch Linux, because it usually has newer library versions and it's the base of SteamOS.