Worldbuilding is not how much info you can dump at the reader. It's as much about when, how, and why you give the reader that information.
Now, there are a couple obvious faults to get started. One, it goes against it's own themes of hardwork. Naruto has not only been made the child chosen by destiny, but it turns out his bloodline has always, constantly been shaping the history of Konoha. Naruto was originally supposed to be about this out of no where kid that no one could have seen coming specifically because he's a no body. Him turning out to have been Minato's son is already somewhat contradictory to that, but to go so much further an make him vital to every important aspect of Konoha since the beginning of time is absurd. And it's absurd because for the longest time, nothing of the sort was hinted for this. The reason this entire history was made up because Kishimoto wanted to strengthen another theme: Rivalry. Naruto and Sasuke's struggle couldn't merely be two guys that have a really complicated relationship, it had to be the ultimate battle of ultimate destiny that stretched through the blood for generations, which is ridiculous. These guys wouldn't know each other if they hadn't been placed on the same team by coincidence. And besides, actual history is messy. It's far more believable when it is the culmination of several hundred figures, both large and small, remembered and not. To make everything in Konoha history center around 2 clans is just not believable. It simplifies the conflict to a simple "good vs bad" fight Uchiha's and Senju are characterized by these 2 simplistic philosophies of "Power of FRIENDS!" vs "Power of HATE!" And it renders the rest of the characters null and void. Just look at how the Hyuga's barely get a passing mention when they ought to be on part with the Uchiha's as the top clan of the village. Instead, they just get a footnote because there's no way some random other dude, even the 3rd most powerful kind of character in the village, is going to affect anything between the two rival clans.
With all that in mind, does Naruto's worldbuilding feel natural or believable, just because there is a lot of it that was dumped on the reader past the point where anything should have mattered? I haven't read the final chapters myself, but my understanding is that Madara was already viewed as a bad guy, and Senju as a good dude. I know Kaguya is some wierd shit that happened later, but I don't understand why this whole senju vs uchiha thing even needed to be revealed in the first place. Wasn't it enough that Madara wanted to mess anything up because he was fucking insane, which is what his motivation amounted to anyway in the end?
It'd be cool to, like you have said, discover other countries, but simply having information dumped for the other countries wouldn't have necessarily made it good storytelling. But Kishimoto forgot about what that word meant a long time ago.