Kevin wants to upgrade his TV and is wondering if HDR is important. Leo says it is. He won't see a lot of HDR content just now, but moving forward everything will come out mastered for HDR. So he'll be on the right side of that by getting an HDR compatible TV. He won't really see 4K broadcast for the next few years, though. He'll get it from streaming sites like Netflix and Amazon. He'll also want to get a UHD-HDR BluRay player. Leo likes the Xbox One S.
As for TVs, Leo likes his LG OLED B Series. It has the same panel as the more expensive TVs. TCL is less expensive, as they're trying to break into the US market, and they may offer an equivalent TV for a lower price. So Kevin could take a look there. Then there's Vizio. But remember, if it looks good to him, it's good. He should also make sure to get a new HDMI cable.
Sitting 8' away, he can get a 55" TV.