I've been having a strange issue with my Series X, everything had been running fine until a got a Roku streaming stick... In certain games I'd get a black screen for a few seconds, then the picture would come back... This would happen a few times a minute. Unplugging the Roku fixed the issue... Not content with this as a solution I trawled the internet and saw that a lot of people with other streaming sticks eg Amazon Firestick, Chromecast were also having issues. Turns out the fix is simply to switch off Auto HDR on the Xbox. All that does is fake HDR content in non-HDR games anyway so it's not exactly important. Hopefully that helps someone. TV is a Samsung KS7000.