Try the asterisk button on the remote when viewing a movie, etc and this opens a menu on the left side of the screen with options for picture settings, etc. Open picture settings and then you have options to adjust TV brightness, picture mode and other features that change the experience. In reference to your HBO Max question and SDR, that is two separate questions. First, movies are often in widescreen format which gives the black bars above and below the video. SDR is standard definition resolution unless the video was produced in high definition resolution (HDR) so SDR will be default and has nothing to do with the black bars. Not all programming or movies are in HDR. Again you can adjust the brightness and picture mode of what you are viewing. The TV picture and viewing experience is great but I do adjust at times depending on what I’m viewing. Good luck!