Becoming detached from my phone and off-hours email access started over a year ago, and has progressed like this:

  1. Disable all push notifications (except Phone and Messages)
  2. Remove native Mail app plus Gmail and Outlook apps
  3. Install Moment App (tracks screen-time as motivation to use phone less)
  4. Remove Social Apps (I add these back from time to time, but generally keep them off. Instagram is the most-likely exception here.)
  5. Disable Safari access (via Restrictions)
  6. Disable App Store access (via Restrictions)
  7. Remove all apps from first screen.
  8. Black and White screen (via Accessibility options. Thanks Billie.)
  9. Permanent Do-Not-Disturb mode; allowing phone calls and messages from a very short list of people to buzz my phone.
  10. Remain committed to redoing many of these as they creep back in over time.

You should try it. I can help if you ask.