Set a timer on your phone. It's ok to do 'sprints' of boring work: think doing 10 mins of work, get 2 mins of phone, then move it up until you get 45 mins of work and 10 mins of phone or something. When the timer goes off you put the phone down and get back to it.

This advice came from adhd and tutoring kids/teens with adhd. You might try researching more tips there like creating a sacred space for work only, and another for phone; or making punch list of important tasks you can do before phone.

Honestly it's never perfect, and distractions will always be something you need to make space for and work around. Don't beat yourself up, just start again. Every minute is a chance to start again and try something new.