I had this idea, to do a playing game video, where I'd do the pieces for you because you're in the hospital, because I thought it was a good premise for you not actually doing anything in the video. Then I lost steam as I was making this video, and (probably interruped by loud sounds, I don't remember exactly), just gave it up and moved onto something else.
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