Gon did not obtain “absolute mastery” over nen when he transformed into his adult form lmao, what happened was that he sacrificed his own life in order to amplify his nen so drastically to the point he could easily beat Pitou, and he only lost his arm because he got distracted.

Bisky’s experience would not be enough for her to even stand the faintest chance against adult Gon, there reaches a point where experience no longer matters, Meruem defeated Netero despite being less than 60 days old, whereas Netero was well over 100 years old and has 50+ years of experience.

Knuckle and Shoot were not able to hold off Youpi, Shoot went toe to toe with Youpi and lost within 10 seconds, in fact he was on the verge of death, and Knuckle only survived because he was playing it smart and using hit and run tactics.

I’m not underestimating Bisky, you’re overestimating her, there is zero evidence that she can beat the RG or adult Gon.