Yeah seen that vid, good quality.
Your right that many HDR TVs have compatibility but do not have the capability to fully deliver the 10bit Rec 2020 wide colour gamut. They may also be restricted in the quality of highlights they can display with reduced nits.
It currently IS a minefield as also many do not support HDR in game mode. Panasonic have some that will as does Samsung but not sure about others in the UK at least. Really it seems to get the full effect of HDR any TV needs to be a UHD PREMIUM model or of same level of performance to make full usage of it. Looks like it will be next year before the specs for such are in the mid price ballpark as currently it is more the higher end models that can.
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on this link. It is one of the better review sites for 4K and Gaming displays. I want to see someone with a BIG 4KTV showing the game also with 21:9 custom resolution.