As somebody who has in recent years changed habits like this, I agree with you. But its a harsh change at first.

Turning off most notifications is a key step. It changes your mentality from reaction to your device to a proactive action at a chosen time. It's a huge shift and well worth it.

Then I started turning my services off at times. No, I don't need to take a call while driving or check messages in the store. That stuff can wait.

My overall logic is that I don't need to make myself available to any and everyone at any and every time.

Sure, sometimes it bites me in the butt as far as convenience, however my quality of life has improved overall. I am very protective of my time and mental attention now, and I wouldn't have it any other way.

I highly recommend taking small measures to test the waters. Then increase as you acclimate to it.