The real hero of Naruto rock lee and Guy Sensei as some random YouTube video I watched years ago explained it 100% correctly.

To sum it up, basically Naruto says he’s going to be the best through hard work and being the best ninja and the only person who actually does that is rock lee and eventually guy sensei. Naruto cheats with his free power-ups and sacrificing his allies throughout the series and Guy is the ultimate ninja for obvious reasons for those who finish the series- I could not get past the point where they split the stories and started doing giant animal battles, but did get a summary video that explained as much as I needed