if you have an iphone, and struggle with self control, there’s a lot you can do to lock it down through the “screen time” preferences - blocking apps, specific web URLs, etc… you can set time windows, or a time limit. then just have a friend set the passcode for you (this is a separate code from your unlock pin).
i’ve looked into dumb phones - but i really do like having a nice camera, maps & easy texting/facetime on hand.