These complaints don't support each other. You're complaining about an outcome that the author is working to subvert while also complaining that he's making an effort to subvert it (to some degree). Twenty plus years have been spent reinforcing that the story is a destination and not a vehicle. No, Luffy won't die in the middle of this fight and will go on to become Pirate King. Does that make the "how" irrelevant? No, that's not the way any story works. His methods are failing so we are seeing how he comes to victory despite that .
Also this chapter brings something extremely interesting to the table: Luffy is the first person whose "voice" is picked up. We know Kaido has good enough CoC/CoO to pick up voices, but that seems to be the general unconscious thing vs Zou and the Sea Kings. Has Luffy gained this transmission? Is it like that conqueror glare, so strong that it just comes out? He's knocked out and submerged but Momo is picking up specific lines that he voiced quite a while before. I don't know how it seems like Oda forgot that Momo knows his literal voice as opposed to it being hard to discern (maybe crude) or simply too loud... on account of it causing Momo pain and all...