As I was watching Major S2, Goro's arrogance[confidence(?)] reminded me a lot of Tatsumi. I kept comparing the two characters. They both also have the determination to fight from the bottom and become the best.
They are also both enjoy sports anime.
Both anime are about baseball, both main characters are not intelligent however they are excellent at baseball and get stronger as the story progresses.
However Major focuses more on the protagonist while diamond no ace goes more in depth into the entire team and the other teams.
"Kaidou Arc" in Major reminded me a lot of "Pro-Hunter Exam Arc" in HxH. Two main characters have to team up with other applicants and to pass the qualifying examination they have to trust other members even if they are complete strangers. Both shows have other similarities, but I won't spoil it. Things often get nail bitingly intense each episode, prepare yourselves for unexpected turn of events. If you enjoyed one of them, you can get the same feeling from the other one.
Both sports animes about an immensely gifted son and all the effort, work and sacrifice it takes to live up to his own potential. (I put the recommendation on S2 of Major because of the age similarity, but you should start at S1 if you're going to!)