Please subscribe and like this video :) In this video I made its quite short, if you'd like me to do a longer version of it, I can do that sometime. Also I am aware that you can see my fingers holding the camera in the video, sorry about that :)
To listen while using other apps, switch the player to Picture-in-Picture (PiP) during playback — it keeps playing in a small floating window (the screen stays on).
To listen with the screen fully off, in-browser playback stops by YouTube's design. Open the video in the YouTube app to keep listening where background playback is supported (e.g. with YouTube Premium).
Open in YouTube app