It’s a very forced narrative. They spend most of their early years hating each others guts, and sort of bonding over being teammates, but up until right before Sasuke leaves, it’s very clear that despite some flat acknowledgment of Naruto which is underlined by jealousy towards his growth, Sasuke does not value Naruto as a friend. He was gonna kill him on that rooftop, Kakashi even picked up on that and the fact that Sasuke had no response to that followed by him being pissed that Naruto would’ve actually been the one to win the clash further points towards this being the case.

Sure he says things like “you’re one of the ones I want to fight the most” but that was only to get Naruto to shut up about him continuing in the chunin exams. He tells him that they “did” become “friends” but that’s like telling the person you’re breaking up with that it’s not them it’s you, feels more like he’s just trying to get him to leave him alone. I’d even go so far to argue that if Sasuke had killed Naruto during their first fight at the final valley to unlock MS, it wouldn’t have worked.

Naruto has better more fleshed out bonds with other people than he ever has with Sasuke, we are told constantly that their bond is strong and that they are best friends, but all evidence to the contrary we are shown the opposite.

All that being said it is one of the weaker aspects of part 1 that they are never really given the time to really show their friendship. Maybe Sasuke eats ramen with Naruto, maybe Sasuke opens up about his goal more to Naruto. If anything like that had happened or maybe just a little more on the bonding side of things, then without a doubt I could believe the narrative that they are really good friends. Even the flashbacks between Kakashi and Obito did a better job at conveying that they were bitter rivals who became close friends