VRR works really well already - some Nvidia users might lose extra functionality like Reflex Ultra that, when paired with VRR, can smartly adjust the frame rate cap. But VRR itself works.
HDR is a difficult beast though… It’s hard even on Windows, and very problematic on Linux (though with Gamescope, KDE Plasma and Wayland you can kinda use it already).
That’s a loophole that can be used indeed, but keep in mind zero calorie products actually do exist. As in, they have zero calories at all.
Frequently these artificial juice packets are truly zero calories because they can be made with a simple acid, some food coloring and an artificial sweetener that can’t be absorbed or digested by your body.
Such a product does have calories in the physical sense (you could combust them) but they have zero calories from a physiological sense.