Here’s a thought:
Zoro will not fight against Mihawk during the final war but after that. Mihawk will never be on the enemies side and why should they fight during an all-out war against the WG? It’s not the right time. Luffy also said that he wants to beat all four Yonkos. So here’s my guess:
Before Laugh Tale we will get Luffy and Zoro vs Kid and Killer.
After the final war we will get a post war arc where Luffy and Zoro will fight Shanks and Mihawk.
Both will beat them and reach the top of the world