Thanks for the A2A.
You are thinking about this all wrong.
First, the 20/80 rule is no longer valid. It just isn’t. Don’t let anyone tell you it is. They are misinformed. All smartphones do the battery management for you. In fact, you are far better off plugging your phone in — and leaving it plugged in — as much as possible. It won’t overcharge (it will go into a “trickle charge” mode), and by doing so you will preserve charging cycles, which is far more important than keeping track of the percentage to which your phone’s battery is charged.
Just use your phone. You won’t damage the battery’s health.