I think it switches betwen rec 2020 and 709 matching the content. I have a C7 series one. It also suport 4:0:0 and 4:4:4 besides 4:2:2.
But im not sure what color gamut is, but maybe its true that is pushed to wide. All content seems like hdr. But as oposite to incresing saturatio/color like in store mode with this config colors seem beter, specially in retroarch, wiouth any deterremt in picture cuality at all. Ist not like increading saturation/gamma or store mode. Maybe its not calibrated for image edditing and its not as acurate to original content, but i like it way better this way. But sometimes specially on youtube the color seem the same so it seems to swich to rec. 709 if explitity rec 709 its on the metadata of the vid playing. This increse in color impresiveness i onlly sure happens in retroarch and the nvidia UI (wolf ATV launcher mod) in anny way i havent seen any tradeoff in contrast brightnes or anything innpicture cuality. Im not so concern about acuarancy than geting the best picture quality posible even if the original content didn,t have that picture cuality. So for me this seem like the best settings. Anyway i will try to research the topic and be vigilant if anthings loos worse thsn before. But as i said im not using my tv for image/video edditing or any tast that requires image precision calibration, so if have better colors that it should i dont see the problem.
If i did not understand your point (im just discovering about this modes) ornany of my argumentation/thoughts about tye isua are wring, please feel free to school my ass, im here to learn.