Problems getting 3 rings with charge moves pvp

Hey, maybe someone else noticed the same thing. I used to get 3 rings (max power) everytime, using two fingers to tap as fast as possible during the charge attacks.
I went to a boulder tournament and at my 5th match, after tapping my mobile on 4 previous matches, i notice that it gets harder to reach 3 rings, in fact i only get 1 or 2, 3 only if i really try to hit it hard and only at the last second, when i used to comfortably get 3 rings without much effort before.
Still today its noticeably hard to get max power out of my charge moves, and im afraid of tapping harder as i dont want to f* break my phone.
Personally i wished the charge system was different, rn its just tapping like crazy risking breaking your phone with no skill, some people might not be able to tap that fast if they have some chronic disease or something. I would like to see something like a slider that you must hit at the right timing and the power is greater the closer you get to that, similarly to nice, great and excellent catch bonus.

Has anyone else had any problem because of excessive phone tapping?