There’s an old argument about whether story or character comes first in a novel; and an old answer, that you can’t have one without the other. ‘What’s a story but character in motion?’
Sounds good and it’s sort of true. You can’t have one without the other, but you can have more emphasis on one than the other. Semi-autobiographical novels typically have plenty of character, but not as much story as you need for a genre novel.
Anyone who phrases the question, ‘What’s a story but character in motion?’ is already loading the dice. How often do you hear it phrased the other way round, ‘What’s character but the motivations for a story?’
Semi-autobiographical fiction has only as much story as you get by bombarding your character(s) with events and observing the reactions. You’re not likely to arrive at a story which builds up on itself. That kind of story that needs thinking about in terms of story-arc.
I like to think of characters as character-arcs too. For me, the word arc implies a strong overall shape to the development a character goes through in a novel. Not a multitude of small reactions, this way and that, all over the place—but a sequence that builds up.
A motto I repeat to myself is: a character should be bigger and more interesting by the end of a novel than they were at the start. They should have gone somewhere and got somewhere.