I watched the show on the History Channel called Secrets of the Dollar Bill and decided to share some info! I'm obviously NOT an expert so it might not make sense but i hope it relaxes you anyways!
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