I've had some realizations about flashbacks. Mainly, that yes, I can have them. All the advice I'd read cautioned against flashbacks, saying that there was surely a better way to show backstory. That you should sneakily ease in that exposition throughout the story. That flashbacks break up the narrative flow, and readers can't wait for them to be over.
But you know what? Fuck that.
I recently read Six of Crows by Leigh Bardugo. It's mainly about a heist, but it uses flashbacks to reveal the histories of the main characters, and they are so good. You get just enough of the backstory to wonder what happened next, and then it cuts back to the present.