67 chapters and 239 episodes in, it's safe to say that the characters of Boruto: Naruto Next Generations have grown a lot since they were introduced, and the eponymous Boruto Uzumaki is no exception.
The trials and tribulations he's faced have made him a stronger and more well-rounded character, although perhaps not as much as some of his compatriots. There are a few important points in the story that can be identified as catalysts for Boruto's growth, and lead to tangible changes in his personality.
Tough Love From Kakashi
Unlike his father Naruto's days at the Ninja Academy, Boruto stands out as a ninja from the very beginning, being something of a natural leader to his class, but sharing his father's reckless tendencies, disregard for authority, and love for pranks. Another major trait that separates Boruto from Naruto, who always wanted to be Hokage, is that the former at first lacks a solid goal. Instead, he was going through the motions, not thinking heavily about his future.
Kakashi, at this point the retired 6th Hokage, finds this unacceptable and firmly believes that Boruto, in spite of his natural talent, lacks the conviction and mindset to become a ninja. At the graduation exam, Kakashi easily takes down the younger Uzumaki when he tries to challenge him alone, and threatens him with permanent failure to become a ninja. Eventually, Boruto works together with his classmates to subdue Kakashi, and they all pass the exam, becoming Genin.
Boruto eventually finds that his goal is not to become Hokage like his father, but rather to be a strong protector of the Leaf Village like Sasuke, who takes him under his wing. Regardless, after his confrontation with Kakashi, Boruto grows more aware of the importance of teamwork and conviction in his life as a ninja. While always kind, he also has an arrogant streak, which has faded to some degree since these events.
Improving Relationship With Naruto
At the beginning of the story, Boruto's relationship with his father is tense. Naruto's job as Hokage often keeps him away from his wife and children, and consequently Boruto feels resentment towards him. Initially, he disappoints Naruto by opting to take shortcuts when they come along, such as using scientific ninja tools to cheat in the Chunin Exams.
Momoshiki and Kinshiki Otsutsuki's invasion changes things. Boruto watches his father's valiant efforts to defend the village first-hand, and for the first time in his life begins to understand not only why Naruto's job is important, but also just how powerful a ninja his father is. After Boruto helps to defeat Momoshiki, Naruto, in turn, makes a stronger effort to get to know his son and foster his growth, and their relationship improves dramatically.
While they do share many traits in common, another way that Boruto is different from Naruto is that he rarely wears his feelings on his sleeve. He is often hesitant to say how he really feels when it comes to Naruto, but gets better at this over time. Boruto's and Naruto's increasing mutual respect over the course of the story is one of the most gratifying things about Boruto.
The Costs of Kama
After Momoshiki's defeat, Momoshiki implants his genetic code into Boruto, eventually seeking to use his body as a sacrifice to re-manifest. This is known as Kama. He also comments on Boruto's unique right eye, the Jougan, and comments that it will take everything from him. Not unlike his father's status as jinchuriki, Boruto essentially becomes an unwilling vessel for Momoshiki. Around the same time, another Kama user, Kawaki, is taken in by Naruto and becomes Boruto's adopted brother, as they are both protected against the organization Kara.
Boruto matures significantly over the course of this arc, and begins to slowly realize the gravity of the situation he faces, especially when Sasuke loses his Rinnegan and Naruto his status as a jinchuriki in their fight with Isshiki Otsutsuki, making them permanently weaker. Boruto almost loses his life when fighting against the Kara member Code when Momoshiki takes over his body, but Kawaki attempts to kill him to stop this, a plan the two agreed upon earlier in order to protect the village. Instead of the attack killing Boruto, Momoshiki decides to intervene and save his life to save his own, but is now unable to re-manifest. This comes with its own costs, as it means that Boruto is now essentially a full Otsutsuki that can be sacrificed to Ten-Tails, which is Code's goal. In many ways, this is similar to the Akatsuki's goals for Naruto which led to the Fourth Great Ninja War. As such, Boruto finds himself in a position of great danger, with his father and mentor far less capable of protecting him.
At the beginning of the story, it didn't seem like Boruto would be forced to bear such a burden, and the impact that it will have on his personality post time-skip is something to watch out for. Expect to see a calmer, more cautious Boruto than before, especially because he now knows that the village's fate may rest largely on his shoulders.