The 'authorship' of Naruto doesn't matter. They're canon if you want to believe they are, and really- why invalidate things for yourself, you're ruining the experience for yourself.
Ignore NB, enjoy the canons, anime and games. It's all Naruto. Never got why people enjoy denying it.
I just don't get it, Kishi approves them as part of the world he created, he's letting one of them expand his world with the new Boruto manga not written by him...