This is a little sort of experiment; the picture is live, of my living room , and I am typing on my tablet clamshell keyboard. I wanted to try it out, but I think the typing sounds may be too loud. If you are going to use this to fall asleep too, check it out first to make sure it won't be too loud. Also my dog growls at the beginning, but it doesn't last long. There are also some paper sounds but it's mostly just whispering and typing sounds.
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