Now what karin says about the kages is true but about naruto thats a lie. First naruto had his chakra by birth even without kurama he would've been able to do a lot and that is strictly proven within the boruto manga
the fact is that thos kages work hard for those techniques for example is not like tsunade was born with godlike strenght no she work hard to get that strength
I can see 2 ways that something like this can happen outcome 1 is if hinata cheated on naruto with someone who he either knows or doesn't knows outcome 2 if hinata died and hanabi walks up to him confort him outcome 1 has so many different people who hinata can cheat on naruto with someone who he either knows or doesn't know but i don't see too many of the second one the people who create these fan made what if stories are probably thinking about trying to decide whether or not if they can use the second one of my outcome stories to though people i will give you the chance to do the second outcome story for a what if story
So far it's not really a what if Naruto married Hanabi story. But I guess the setting and background needed to be set first. Still little annoying the main point of the story was a brief interlude.