Hi NightNight Fam! Sorry for another long break, the school is finally over so I have more time to actually record some videos for you. Hope you're all doing okay! ~ Jules.
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