I hope you enjoy this video. It took a while to render properly onto my phone and after a few attempts it's finally let me upload it to YouTube :) I hope this video is ok. :)
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