My protagonist is a 13 year old boy who's very optimistic and child-like. So far my conflict(?) for this character is that he's supposed to join other characters to, put very simply, save the world, but he's been sheltered and really isn't ready to jump into something so big when his mind is on being friends with everybody.
My problem is that there's already so many optimistic characters that are like this. Spongebob, Wander, and Steven Universe are the first that come to mind. Also the fact that my character is immature and sometimes I feel like he's just a kid character who is just there to look cute and be a plot device more than an actual character (nothing specific in mind but there's a lot of child characters in animation who fit this bill). Sometimes he feels so bland, but I don't know what to add without changing him so much that he isn't the same character anymore.
What can I do to make my optimistic character stand out from other optimists? How do I make him more interesting so his personality more than "the child character"?
Source: reddit post