Series X - HDR settings resetting when console re-started

Check your TV settings: If you are using a TV to watch content on your Xbox Series X, check your TV settings to make sure that any power-saving modes are turned off. Also, make sure that the HDMI input you are using to connect your Xbox is set to a mode that allows for HDR and 4K content, if applicable.

Reset the display settings: You can try resetting the display settings on your Xbox Series X console. To do this, go to Settings > General > TV & display options > Video modes > Allow 4K > Allow HDR. Make sure that both of these options are turned on. Then, go to Advanced video settings > Video fidelity & overscan > Display > Calibrate HDR for games. Follow the on-screen instructions to calibrate your display.

I had the same / similar issue with my old 4K 60hz none HDR / HDMI 2.0 monitor when watching movies and some times in games with the Series X,

As soon as i upgraded my monitor to a 4K 144hz monitor that has HDR / HDMI 2.1 ports, i no longer had this problem,

I'm not sure what the problem is, but my guess is that the HDMI 2.1 port on Series X doesn't play well with HDMI 2.0 port of monitors, or it's the Series X trying to force HDR on, even if the monitor does not have / support HDR and the HDR in Series X menu's is turned off.

my xbox series X is playing up i have no game audio for xbox one and series X games, xbox 360 game worked fine, i reset my console kept games and apps and no audio still. i dunno ill call support when i can, Im using samesung 4k hdr qled tv and it worked fine a few hours ago and then just stopped. and last few months been having no menu sound and start up sound too issue now no games audio

Let's try playing the game to the Xbox One first then save it again then go back to your Series console check if it let's you play the game. It seems to be that your saved data is not syncing properly with the Series X console. Also, try turning off HDR.

On your Xbox go to Settings, go to TV and display options.

Set the resolution to 1080

Under Advanced to the right click on video modes

Uncheck Allow 4K and HDR10

Restart the console then start the game.

I have the same issue on my Xbox series X I hard reset the console and now its worse than before I reset it. I started up my Xbox one X and no issues with that when I started up a game.