Is a passive protagonist at the start a problem?
A protagonist who will not act at the start is the defense working correctly, and what they have surrendered is their say rather than their energy.
When the wound does not name a person, every later part of your story quietly invents its own version of the loss, and because each line reads fine alone nothing announces it.
Write "they lost someone" and every scene that touches that loss will quietly make up its own version of it.
The event that wounded your protagonist is what StoryDNA calls The Trauma. Everything points back to it: your premise, your inciting incident, the reason they can't just walk away. If it names a real person, all of those point at the same human being.
If it doesn't, each scene grabs whatever version of the grief sounds best right there. Every sentence works on its own, so nothing warns you. Each part is good, and the whole thing is about nobody.
So name a person, an age, and a place.
In Get Out, Chris has all three. His mother. He was eleven. He sat in front of the TV and didn't call anyone while she lay by the road for hours. That's why his politeness reads as a symptom, not just his personality.
Then make the story keep it close. In Jaws, Brody stays away from the water, and the story puts him in a beach town that can't afford to close. He can never get away from the water.
Nobody has ever recovered from "a difficult childhood." People recover from one thing that happened with one person, at one age, in one place.
Write down who it happened with, how old your protagonist was, and where they were. Then check that every scene that reaches back to The Trauma reaches back to that same moment.
A protagonist who will not act at the start is the defense working correctly, and what they have surrendered is their say rather than their energy.