Not sure about Facebook, but Google is already beta testing exactly what you're talking about: https://www.theverge.com/2018/8/6/17655520/google-digital-wellbe

Not sure about Facebook, but Google is already beta testing exactly what you're talking about: https://www.theverge.com/2018/8/6/17655520/google-digital-wellbeing-beta-now-available-dashboard-app-timers-wind-down https://www.theverge.com/2018/8/6/17655520/google-digital-we... I have it on my Pixel 2 and it works great.