It doesn’t matter what kind of character is at the centre of a story, they will all face the same fundamental issue. Something needs to be done and they have to be the one to do it.
The world needs saving, a toy needs buying, or a heart needs winning, but before you get to that, first the character has to make the determination that they are going to act rather than give up and go home.
Whether they succeed or fail depends on the story you want to tell, but whether they try is not up for debate, because otherwise you wouldn’t have a story. So you have to have a character that decides to act and keep going no matter what. But what is that makes them unable to walk away? Understanding what drives them will provide you with a core element of the character, and the driving force behind your narrative.