I think 'Naruto' could be comparable. It has similar elements of action, adventure, and character arcs. The themes of friendship and determination are present in both 'King of Thieves' and 'Naruto'.
One manga that could be similar is To Love-Ru. It has a similar light-hearted and romantic tone with diverse characters and comedic situations.
I think 'Our Secret Neighbors' could be similar. It has a focus on neighborhood relationships and character growth like in 'Close as Neighbours'.
I'd recommend 'Tower of God'. It shares similarities in terms of the main character's solo adventure and the gradual increase in their abilities, similar to what you find in 'Level Up Alone'.
It's quite good. The adaptation stays true to the manga, with the storyline and character development being accurately represented.
Overall, the management of Hack Link manga is impressive. The story is well-structured, and the characters evolve in a natural and interesting way. There are no sudden jumps or inconsistent developments that would confuse the readers.
'Hunter x Hunter' is comparable. It features unique powers, strategic battles, and a focus on character growth and their relationships, much like in Naruto.
I'd recommend 'Paradise Kiss'. It shares some similarities with Nana in exploring complex relationships and the characters' growth and struggles.
Maybe 'Honey and Clover' is comparable. It delves into the emotional lives of young characters and their struggles, much like in Oregairu. The art style and character dynamics can give you a similar vibe.
I think Tower of God is quite similar. It has an engaging plot and well-developed characters like SoloLeveling.
I'd say Naruto. It has a vast world, diverse characters, and an epic adventure similar to One Piece.