I wasn’t sure if this was a prompt or a question, anon-friend, but since I’m not writing D:M prompts I decided to take it as a question. =)
And apologies ahead of time! This is going to be kind of long, and it’s not really going to answer your question, and that’s only because it touches on a theme of questions/comments that I’ve gotten over the years (on tumblr and on ao3) and I always kinda dodge talking about it, but I figured it would be better to finally write out my thoughts on a post that I could point people to, the next time it comes up. So my long response is only because this is giving me the opportunity to talk about it!!
But yeah, I get variations on questions/comments that moderately boil down to, why don’t you write about Hinata’s past in the same way you write about the other Miracles. And as for your specific question, I will say that I am definitely not qualified to write about abuse/trauma with any kind of authority, so I can only talk about (for lack of a better phrase) authorial intention.
As a fanfic writer who primarily writes AUs, I make it a personal goal to always try to work with canon, so that canon dictates the rules of my world building and my characterizations. Kuroko no Basuke and Oofuri, canonically, are stories that lend themselves better to exploring trauma recovery than Haikyuu is. I would say KNB and Oofuri both explore themes of overcoming your past, whereas Haikyuu’s main theme is always looking to the future.
One of the things I love most about Hinata as a character is that he’s fundamentally optimistic and doesn’t dwell on the negative. I finally got caught up on the 4th season (juuust in time for new episodes to come out) and that arc really makes it clear that Hinata doesn’t suffer in the same way others would– a lot of the other characters assume that sneaking into a training camp to only be a ball boy must be the most humiliating/degrading experience, but Hinata genuinely takes the opportunity as a positive experience for growth. Both in that arc, and throughout Haikyuu, Hinata is seen as the character who saves others with his positive outlook.
So, in the world of D:M, I had to reconcile how someone could experience Teiko and still come out with Hinata’s positive outlook in canon, and my way of doing that was the disassociation of Hinata deciding the past is behind him. It was probably not the most elegant of solutions, but it was really important to me that Hinata has a very different post-Teiko experience than the other Miracles did.
The main theme of “Have a Seat” is that despite what Hinata experienced, he fundamentally believes the world is kind, and so he is met with kindness. It’s a philosophy Kuroko doesn’t fully believe but he wants to, and so he tries to live that way despite it not coming naturally to him. The climatic end of “Don’t Blink” was the characters learning that people can be kind; “Have a Seat” was a confirmation of what Hinata already knew.
So, because of all that, I have always been extremely opposed to writing Hinata as a badass assassin, or as someone who is still trapped by Teiko, or exploring his trauma. I wrote one short where he does have nightmares, as I think that would only make sense, but I have always tried to stay true to my view of Hinata as a character, which is someone who remains positive in the face of adversity and looks to the future.
Sorry again for this long explanation! I just really wanted to take this opportunity to explain a few things that have haunted me over the years. Thank you for asking, anon-friend! =)