I have a 60hz 4K tv with HDR but the HDMI version is only 2.0 and not the upgraded 2.1 XSX offers. So l started worrying if l can still benefit of 4K/HDR/60 FPS or am l going to only get 4K/HDR/30 FPS. Web search doesnt mention HDR bandwidth requirements anywhere afaik. Yep! It is sufficient enough but will do some weird things to color that
Freesync is a 3rd party technology. We officially support the industry standard HDMI variable refresh rate (VRR) over HDMI 2.1 specification on GeForce RTX 30 series and above." You can't with an Nvidia GPU. Connect it via DP for G-Sync. HDMI 2.1 does support G-Sync, but the 2080 doesn't support HDMI 2.1.
Generally speaking though, if it has HDMI 2.0 yes it should be able to do 4K 60Hz 4:4:4 but it is best to know the details for the TV set you are interested in purchasing. Like others mentioned you need a GPU which can output the proper signal too, so a GPU with at least HDMI 2.0, preferably 2.0b.