When my child is heavily dependent on digital devices (games, videos), how should I respond?

Digital rewards are "instantly fun," so just cutting it off tends to send them to another screen. Rather than scolding "stop," it helps to: (1) decide time, place, and content with your child in advance and make it visible (a timer, a schedule); (2) prepare the next enjoyable thing so switching is easier; (3) use parental controls as a system of support. Building the rules together as a family lasts better than a blanket ban. Also prepare favorite offline activities that use the hands or body, so enjoyment beyond screens can grow. If it strongly interferes with daily life, consult a professional.