Does FreeSync work for you on 4k @ 120 Hz 4:2:0? I have a Vega 56 connected to my Q85R and all I seem to get is a green flickering mess as soon as FreeSync engages. Using 4k @ 60 Hz or 1440p @ 120Hz on the other hand works fine with FreeSync.I don't have a 3080 but with RX 5700 I have 4K @ 120 4:2:0. If anyone does not have it and source is able to provide it, then the problem is the HDMI cable and not the TV. There are many "high speed HDMI" cables that are not really what they should be.