for me this:
Sometime before the Final War imo. I feel like by the time the final war rolls around, some of the Straw Hats would have already achieved their dreams and others will achieve while it is taking place. Though for Zoro in particular, I feel like he finna pull up as the WSS to the Final War. Because we already know Luffy will pull up to final war as the Pirate King (the Final War is
heavily implied to go down after the One Piece is found; meaning once Luffy beats BB to Raftel, the World Government is next). So I think it makes the most sense for Mihawk and Zoro’s fight to take place sometime in between the defeat of the BB Pirates and the Final War.
Definitely not in Elbaf though, that figures to be soon considering Elbaf is looking like the next arc post Wano.
or this:
Probably right before they go to Raftel because Luffy wants WSS in his crew when he becomes Pirate King.
Though Raftel is not the end of story, that much I am 101% confident on, its learning and then acting on it.
also if we are getting an Elbaf arc and it comes right after Wano then i dont think Zoro will face Godahawk there. Hawk will be still too much for Zoro next arc. he will need to grow at least 1 more arc after Wano to surpass Mihawk imo. the difference between the two is still too much.
while Zoro didnt go all out during Dressrosa but his ISDS so far was his biggest AOE move which he used to bisect the golem close range. even if he got stronger in Wano i doubt he can do what Mihawk did with the iceberg.
Mihawk iceberg slash was still bigger and his was an casual ranged slash and it was done unintentionally.
so Zoro needs to complete the following To Do List just to be on the same lvl as Casual Mihawk:
1. ISDS lvl casual slash
2. ISDS lvl casual slash w/o haki
3. ISDS lvl casual slash w/o haki from some distance
4. ISDS lvl casual slash w/o haki from like a 1km away
5. ISDS lvl casual slash w/o haki from like a 1km away while being unintentional
when he does all of that then we will talk about Zoro taking on Mihawk

depending on how Oda handles Zoro and how far he wants Zoro to raise, i can see Post Wano Zoro achieving upto number 3. i cant imagine 4 and 5 done by Post Wano Zoro

.
and this is just the difference in AOE which so far has been one of Zoro's highlight. imo when Mihawk gets fully fleshed out and see him go all out on panel, current version of Zoro(or post Wano) will look like a scrub against the Godahawk
