There is no cope whatsoever in Mihawk's haki forging the strongest weapon in the world.
Not Imu, not Roger, not Shanks, not Gorosei, not Whitebeard or Rocks or whoever you pick.
Indeed, Kaido's top 5 tells you everything you need to know about Mihawk but I am not sure if you have figured it out yet.
Yes, Gorosei are people with a single devil fruit.
Those people are just hype tools for people with multiple devil fruits.
And those people are Blackbeard and Shiryu.
The best part is when the most absurd takes you have ever seen end up coming true.
There is no headcanon about Mihawk forging the strongest weapon in the world thanks to his haki. Not Imu or anyone else.
Everything else is common sense that you keep refusing because of your agendas.
If someone else's haki was stronger than Mihawk's they would have forged their weapons into stronger than Yoru but they havent.
Only Zoro will manage to forge a stronger weapon than Yoru and he will do it with his will(haki) just as Mihawk told him to.
The sole fact that Mihawk is the wielder of strongest weapon in the world tells you everything.
Imagine being Imu, "the ultimate villain" and not having a weapon stronger than that of Vista's rival...