There is a way to turn off the screen while content plays over audio only. However, it requires numerous clicks to navigate. More while playing a video. How can this function be accessed more easily? Here is the built-in method to access. It sometimes shortcuts to the audio settings screen but that changing condition isn't necessarily a good thing.

Settings, Settings, Display & Sound, Audio, Advanced Settings, Audio Only Mode, (ok or wait 10 sec).

This translates to these button presses:

Settings button, down, down, ok, down, ok, down, down, ok, down, down, down, down, ok, down, ok.

I downloaded Smart Tube Next and that dramatically reduces the number of required clicks but only works in that app. I would like to use this in any app by accessing the TV's function. I cannot find a way to reach this function quickly. I want to map it to the Mute button on the remote since I pass through audio via toslink cable anyway.

I've dug through the file system and haven't come up with anything. I would greatly appreciate any suggestions and welcome discussion from others. The fact that this function appears in the YouTube replacement app, indicates that the developers deemed it to be a useful-but-omitted feature in the official app.