For me it's not the phone that's stopping me from reading books but my computer, on which I play games, and browse, and do private stuff.
Where I live, electricity price is so ridiculous, I leave my PC off for 3 to 5 hours a day.
You get bored after 5 minutes. This is the best time to open your book and read.
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Same idea applies for the phone. Just leave it off.
It's difficult to turn your phone off if you have a spouse or children or other dependents who you can't drop communication with for hours at a time. But it's helpful to strip it down to the essentials so it doesn't double as an entertainment device.