DIAGNOSIS This is almost always caused by the wrong HDR setting being forced, or the 'Adaptive Brightness' feature misbehaving. The TV is trying to adjust the picture for content it's not actually displaying.
FIX Go to Settings > Display & Sounds > Picture. First, check your 'Picture Mode'. Set it to 'Movie' or 'Standard' as a baseline. Next, scroll down to 'Advanced Picture Settings'. Turn off 'Adaptive Brightness'. Also, look for 'HDR Mode' and set it to 'Adaptive' (not 'Always On'). Finally, go back and make sure 'Color Space' is set to 'Native'. Back out and check your content.
IF THAT DIDN'T WORK The issue might be with the specific input or app. Try a different HDMI port with the same source, or try a different app (like compare Prime Video to YouTube). Also, perform a soft reset: hold the Select and Play/Pause buttons on the remote for 10 seconds until the screen flashes.
HEADS UP Some streaming apps, especially older ones, send incorrect color signals. If the problem is only in one app (like Disney+), check that app's own in-app settings for a 'match content' or 'HDR' toggle.