“You could say that it’s my responsibility” to exert self-control when it comes to digital usage, “but that’s not acknowledging that there’s a thousand people on the other side of the screen whose job is to break down whatever responsibility I can maintain.”
Pin Friend (for iPhone)
Delete all the applications that you don't actually want.
Ask a friend to child block your iPhone with the Parental Restrictions feature using a pin that you don't know so that you can't install new applications or use Safari.
This is a way to turn an iPhone into a dumb phone, but with google maps.
Freedom (for iPhone, Mac, Windows)
bonus: consider setting a recurring block using Freedom, and then asking a friend to set a password which you don't know.
If you are able to, go camping and leave your phone in a bag the whole time (unless you have some kind of emergency). Use an auto-response to tell friends when you will be back on the grid.