Unironically, Akainu is a very scary opponent no matter how strong you are. One wrong move and you can easily get horrible, irreversible damage to your body. I'm kinda worried about Luffy's condition after he fights him as well as the possibility that he goes after some of the other Straw Hats.
my future matchup for luffy
Elfaf arc
Shanks as friendly battle/weevil/ evil giant guy
Laughtale
Blackbeard - mastered awaking devil fruit for luffy and improved time for gear fourth
Final war
Akainu.
Now people say luffy will fight IM guy instead of Akainu but it will monkey d dragon or sabo will fight IM first.
I think luffy master gear fourth and awaked forum to fight akainu. I believe it wil be best fight for oda to draw.