So i did a quick video outside! I think it sounds ok, i thought it was going to turn out bad. This video has been uploading for like 30mins. Finally it's done! My shadow is horrible!!
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