How Loud should video playbacks be? LUFS measure?

[DThompson55]

Is there a recommended loudness measure for video playback on Zoom? Streaming services often ask for between -12db and -14db LUFS. Really the question is about consistency. We don't want listeners turning up their volume to hear someone talking, then play a video and they have to turn their volume back down. It's not really clear how to manage volume easily across multiple sources like that.