Way to take the credit from the guy. Luffy had formal training in everything that Zoro learned too. Yet it took him as long as it did to reach the level he did. Zoro just has a better affinity with Haki than Luffy. I don't get why people can't accept anyone being better at something than Luffy.
No, what I mean is Zoro attained Adv CoC easier due to Enma and him knowing Haki concepts since he was a kid. Breath of All things is observation and Armament Haki concepts.
Luffy on the other hand never knew any Haki concepts as a kid and still mastered the basics of all 3 haki 18 months, and then mastered all 3 advanced Haki in 2 years and 3 months.
Even then Zoro needed Enma to what Luffy does naturally with his Haki, as well as it unlocking his Conquerors Haki.
Meaning Luffy's haki talent far surpasses Zoro's by a country mile. His Haki is stronger and he is more skilled at haki than Zoro despite Zoro knowing about it longer.