4K glitch

I’ve a 4K UHD TV. Once I first received my TV the video games we’re taking part in on 4K it was brilliant an vivid an seems to be nice. However now after I play that very same recreation it seems to be paler an it’s not taking part in on 4K. That is occurring with my different video games too. Once I go to my video settings it’s set on 4K UHD. I simply don’t know what to do. I’ve tried each hassle taking pictures methodology I can consider a fair tried resetting my Xbox. I used to be even on Microsoft for an hour making an attempt to repair the difficulty however even that they had no thought what was occurring.