Parental controls - airplane mode
Is there a control/app that will allow me to put my children’s phones in airplane mode at a certain time of night?
iPhone 11, iOS 13
If you have family sharing set up, and you are the organizer, you can set up screen time (from your phone) on their phones. https://support.apple.com/en-us/HT208982
Near the bottom of the article I linked above there are instructions for doing this.