Willpower loses most fair fights. So stop giving it fair fights. Put the phone in another room.

Willpower is a poor plan because it has to win every time and the phone only has to win once. Deciding in advance beats deciding in the moment, since in the moment you are tired and the thing is right there in your hand. Changing your surroundings does the work your resolve keeps failing to do. That is not weakness; it is arranging a fight you can actually win.

Before your next block of work, leave the phone in a different room rather than face down beside you. Charge it in the hall overnight. Make the easy choice the right one.