I realized today (by the fall of a tree, long story) that having reliable people in your life--and the knowledge that they are there--is a cornerstone of happiness. Which sounds as if I were speaking hippie, but that doesn't make it any less true. We all crave stability, sometimes more, sometimes less. Having reliable people near us can help us find that stability--or maybe make us go looking for it.
So why do I put a personal insight on the internet? Because I want to use it to make a point about character development.
Stability and the MC: Two scenarios: the MC either has or doesn't have stability. When they do, though the story that stability is just torn apart. After, the MC will find a new stability, and in doing so will realize that what they previously had wasn't really stability, just the status quo.
If they do not have stability, they will be made, throughout the story, to actively pursue it. This can be done by
A reliable person in the MC's life: this need not be a character close to the MC, not even a friendly character, many antagonists I would argue are fundamentally reliable people. But this person in the MC's life gets them moving, particularly if the MC lacks motivation to change in the set up.
Happy writing, she told herself.