Any fight after Mihawk will be just a warm up. No need to go all out against mere Admirals.
Honestly, unpopular opinion but I think its 50/50. I always imagined the Zoro/Mihawk fight would occur prior to the final war rather than being the last fight in the series.
Luffy would pull up to Marygeoise with Zoro as
"The Pirate King & The Worlds Strongest Swordsman" and whomever is guarding that front (IMO Akainu & Borsalino) will be the ones to test the Strongest Duo in the Pirate World.
And its only good storytelling that the Worlds Strongest Pirates would fight the World Governments Strongest Fighting Force the Marine Admirals.