It's hard to say for sure. Deku has grown a lot, but All For One is a powerful villain. It depends on various factors like their current abilities and the circumstances of the battle.
It depends on personal preferences. Some people think it is the best because of its rich world-building and diverse characters. But others might have different favorites based on their own tastes.
The One Piece anime doesn't cover everything from the manga. There are instances where the anime slows down the plot or adds non-canon material. However, the core storylines and major events are mostly adapted accurately.