Then, within the main Settings menu, select "Remotes and Devices". Within the "Remotes and Devices" menu, look for the section at the bottom labeled "Home Theater Control". You want to ensure that "Control TVs and Receivers" is toggled "On". If this section is grayed out then it means that either your HDTV is not HDMI-CEC compliant, the HDMI Go to “TV Inputs” or “Settings,” then “Inputs.” Look for the CEC or HDMI-CEC option and enable it. Hisense TVs. Press the “Settings” or “Menu” button on your Hisense TV remote. Navigate to “All Settings” or “Setup.” Look for “HDMI CEC” or “CEC” settings and turn them on. Vizio TVs
Turn on your Smart TV. Press the setup key on the remote control for about 7 seconds or until some information appears in the upper left corner. Next, press the 1,1,0,5 keys and press OK. The hidden menu will open on the left side of the screen. If this doesn't work try to see if you can find one that does.

To adjust your TV controls directly from your Xbox Series X|S controller you need to enable the specific HDMI-CEC control. To do so, follow these steps: Press the Xbox button to open the guide menu. Navigate to the tab for Profile & system and select Settings. Highlight General and select TV & display options.