After Becoming Champion, I Accidentally Trigger a Newbie System

After transmigrating into the Pokémon world, she spent three years relying on herself to become the champion of the Unova region. Then, on a flight to Kanto, she unexpectedly activated a beginner system.

Looking at the Poké Balls at her waist containing Hydreigon and Haxorus, she thought: a beginner, huh? Fine! Gym leaders of the Kanto region, are you ready to be challenged...

(No female lead, no female lead, no female lead; important things must be said three times. There may be female characters in the middle, but the focus is no female lead, with adventures across different regions.)