I felt like brushing my dog, as her hair is so long. I thought I would make a video of it. She did fall asleep and start snoring, so I hope that isn't too loud. (She's an English Springer Spaniel)
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