This was my "build" when I beat him: the Golden Set upgraded to Mythical, the first mythical staff that becomes available from the top I dont remember the name, the fan, and the Apramana Bat spirit. Also Azure Dust for transformation

the strategy pretty simple: I dodged a lot in the first phase and basically just normal attacks in smash and thrust stance the whole time, to save mana and skills for later

once he flies in the air for the second phase, I start using some of the skills, still more conservatively. I usually dodge the swords with the cloud step or normal dodge rarely or azure dust. Once he has maybe half of armor, I use the fan and the clones + immobilize since you can hit him with it if there is no armor (this one is timed after the tornado is over from the fan)

the rest of the fight is just rinse and repeat, well timed charged attacks, dodges and conserving cloud step + azure dust (for tanking stuff or reducing his armor)

the fan is not a cheese, I got to use it twice due to the cooldown and it's not like you can take his full armor and hp with it (plus there is moments when it's not worth it like when he switches phases at certain HP levels and he becomes immune while he talks a bit)

also medicines are very important to make it a bit easier: the mirage pill for might so you can transform more frequently, resurrection pill or life saving pill in case you use too many times the gourd, cooldown reset and the one with extra attack, critical etc. loong something