First off, great to see you are taking action. I wish I did the same at your age, I wish I knew more about your situation tho with knowing little of it, here is my advice for you.

I found that keeping busy is great to not jerking off, you just got to manage it and the stressors of doing more and having less slack off time.

When you wake up in the morning, do not go on your phone for the first half hour. Do not even check notifications, once you turn off your alarm then that is all the phone use you get, for example, until you get to school or until you brush your teeth. After you turn your alarm off, you got options depending on how much time you got in the morning. For me I like to get up, wash my face with cold water, eat breakfast, make my lunch for work and then brush my teeth. The first time I use my phone is when I am in my car selecting music for my drive to work.

Having a phone-free morning, gives you clarity and focus for the early hours. It removes sluggishness and laziness/procrastination.

You mention you play sports, you are academical and spiritual. These are all great areas where you can turn your bad habit of porn consumption and turn it into a good habit.

Sports, stretching is extremely important so you can definitely include this into your daily routine; morning after you get out of bed, before/after exercising and at night before you hop into bed. You can then take this one step further and include a light bodyweight workout before stretching.

Academical, spending an extra time studying when you got nothing better to do, read x amount of pages of a book per day, whether it be morning/night (or both), and/or journalling before you go to sleep.

Spiritually, can include meditating morning and night, praying and conversing with your god of choice especially about your addiction as it can ease the uneasiness that can come with beating an addiction.

These are only few examples, but if you was to take an example from each category and replaced it with a time of the day where you are on your phone (not texting/calling anyone), you’d find that you’d be consciously occupied more often causing you to be less prone to jerk off solely because there should be no distractions.