I think the Pomodoro timer helps me focus because of the nature of it counting down. I try to complete a task before the timer ends so I focus more and don’t dilly-dally. Otherwise a task that should take 20 minutes takes an hour because I don’t think about timers that go up.
So an idea would be to use the current stopwatch feature of the Next Page and swap the stopwatch with a countdown timer. When the timer ends you can get a pop up that asks “were you focused?” If you say yes it appends a tomato emoji to the notes (optional) and then you can take a break or do another round.