"Yes, the narrator confirms that Luffy is the winner.
In fact, at the beginning of the chapter the narrator says that the previous result (the winner was Kaido) is going to be updated.
And when the explosion of the underwater volcano takes place, we see a new text from the narrator saying that the winner of the "Decisive Battle in Wanokuni Sky" is Luffy."
Wtf was Oda smoking this arc?
Like for real, this has to be the most anticlimatic resolution to such a massively built up clash in the history of entertainment.
Heck, even the GoT showrunners were heard breathing a sigh of relief and saying "Thank God we're not the #1 bottlers anymore!"
This resolution was so anticlimatic, that the vast majority of fans were sure this couldn't be the end due to various reasons. Heck, even some hardcore "Luffy-certainly-wins-this-round" preachers didn't believe that this mere punch was "it".
I'm not starting with the ZKK debate since it was always blatantly obvious this would never happen, but not only are these fans mad rn, the rest of the fandom is disappointed rn, too.