I'm not shitting on Luffy for having no growth. Development isn't necessarily character growth. But Zoro do have that. It is clearly how he became less naive since Luffy saved him and then he is barely trusting anyone outside the crew.
- His interaction with Tama when she got mad after he told her Ace was dead.
- Stopping Yamato attacking Kaido knowing the scabbards deserve the first hit.
- Breaking the mirror during Katakuri fight so they couldn't attack the weak members of his crew then pretending to be okay so they didn't worry about him and they got on with escaping.
- Telling Jimbei he was his captain and that he ordered him to survive no matter what.
Luffy and Zoro's character developments look a lot different because you cant do a like for like with them.