Here to deliver some tingles for you, join me as I ramble somewhat successfully in an attempt to get you nice and sleepy, leave me some feedback to let me know which triggers worked best for you!
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