There is important detail we all missed in One Piece Chapter 989 . In the code of conduct for Samurai (also known as Bushidō) dictates that samurai must wear their swords on the left hip, regardless of their dominant hand.
Wearing the swords on the left indicates one is ready for action, while the right means you don’t expect to fight.
This means Zoro never took the New World seriously until the last chapter! Finally we will see what is Zoro’s power when he get serious