Apparently there's this theory going around that Mihawk is not the WSS or that their exists swordsmen stronger than Mihawk.
Now let's get this out of the way. Zoro will be the STRONGEST SWORDSMAN ON THE FACE OF THE PLANET at the end of the series. As in no single swordsman alive will be stronger than Zoro at the end of the series.
So now since Mihawk is apparently (to some people) not the strongest swordsman. Who is this Strongest Swordsman who Zoro will defeat at the end of the series.
Why you didn't include Swordsmen Gorosei?
People think that Zoro is going to fight against Mihawk in the last chapters of One Piece but that is BS. Mihawk can't be bigger challenge for Zoro than the main antagonists of the story. What is the point of strowhats defeating the main villains if it isn't their toughest challenge? Defeating WG is the hardest thing ever, if it was easy it would have been done earlier. BB on the other hand have the potential to become even more powerful than Marians and challenge the entire world which will be saved by strowhats.
The antagonists should be the biggest challenge for the Main characters, defeating them should be something impossible there's even chance that they might die after defeating them. So will become the WSS quite soon, I'd say after Wano since Mihawk is camander level, maybe Mihawk will be killed by Shiriu and Zoro will defeat him, the point is, is that Zoro will face people that are more powerful than Mihawk like Admirals, Gorosei, BB pairets etc. Zoro will be Admiral level at the end of the Story.