PS I have linked a bunch of my own productivity articles & systems in my profile in case it can be helpful.
I break up periods of work by checking my phone,scrolling a forum, or working out/playing a game for bigger breaks. If I just sprint it out, i start to lose focus and get distracted far easier either way.
The real help for me is having a dedicated study space and if possible, set time frame outside your control. Im a college student so I frequently head to the library in long breaks between classes and that is my allocated study time/place. It gets you in the mindset and lets you get started on things right away.
Music is also big for me, but it hurts most people. Bossa nova always fits the mood though.
Although I could disable the blockers if I really wanted to, I usually don't.
In the event that the blockers aren't helping, then I'll move my phone to the other side of the room so that it's completely out of reach.