Advice about phone use tends towards the extreme – delete the apps, buy a basic phone, do a detox. Those fail for most people because the phone is genuinely useful.
Structural changes work better than resolve.
Remove the triggers
Notifications are the main mechanism. Turn off everything that is not a person contacting you directly. Not fewer – all of them. Apps you actually care about you will open anyway.
Add friction where you want less
Remove the apps you overuse from the home screen so opening them requires searching. That single step interrupts the automatic reach more effectively than any timer.
Log out of the ones you want to use deliberately. Typing a password is enough friction to make it a choice.
Remove friction where you want more
The books, the notes, the thing you keep meaning to do – put those on the home screen where the others were.
Change the physical arrangement
Charge the phone outside the bedroom, which addresses both the last thing at night and the first thing in the morning. Buy a cheap alarm clock.
Leave it in another room while working. Distance works where discipline does not.
Greyscale
Setting the screen to black and white makes everything measurably less compelling. It sounds trivial and people report it working.
What not to bother with
Screen time reports, which inform without changing anything. And app timers, which most people dismiss reflexively within a week.
The environment does the work. Willpower is unreliable and you should not have to spend it on this.