Well it depends on the Anime I would say most would be Shounin Jump.
First I would not include DBZ cause 90% of the characters are op and once Sora beats someone like Frieza, Cell, Buu, or Broly none of the enemies be actual threat plus the only good out of Kingdom Hearts in Dragon Ball is a running Joke of Sora looking like a sayian.
What Kingdom Hearts needs a series that is well compairable. Shows like Fairy Tail, Yu Yu Hakusho, My Hero Acedamia, RWBY, and Sailor Moon, but I say the best Anime for Kingdom Hearts has to have a main Protaganist as the who starts out as the underdog like Sora, who has a best friend who is also his rival who is popular and later fell to darkness out of jealousy of their best friend, and have a situation where the main protaganist is saving his best friend from himself like Riku. And travels with a loud moth who knows everything and has a bad temper like Donald, along with a goofy yet loyal and smart friend you can trust like Goofy. All while an organization is hunting the main protaganist to do to the power he possess.
Well that's an easy Naruto. The show it's self have similarities to Kingdom Hearts, and hey the Actor who voiced Xemnas in Kingdom Hearts also voiced the Nine Tails in Naruto, the actor who voiced Lea/Axel in Kingdom Hearts also voiced Iruka in Naruto.
Plus unlike Dragon Ball where they would force Z into the game. Naruto has plenty of retold stories and even so they can a story strictly made for Kingdom Hearts.