Nooo~ why did I have to come back when it's a cliffhanger about his trauma... hope we get some much needed revelations. Better if it's through communicating it with Marin since she's not really that great at being proactively thoughtful.
I've re-read very far back, and I think this is just the usual Wakana being confused, love struck, tired, guilty and ashamed. Maybe a bit like how those people who seek revenge feel empty after fulfilling their goal, but in his case he involved Marin in it and it's a crafting project that he want to do to prove himself. He isn't exactly up there when it comes to social nuances, especially in terms of his own feelings and self worth, and now he's gone crazy from the passion project and he would probably feel like he's treating Marin like a dress up doll instead of herself.
With how Haniel is portrayed, this arc is definitely about Love that is twisted and unreachable... he already feels that way with Marin, and with her cosplaying the cruel angel it's become even more convoluted in his mind as he draws connections to himself and Haniel and the people that dies due to the angel.
He doesn't know yet that it's
love love that he is feeling for Marin but he knows it's because of beauty since it comes from about the same place (Dolls = pretty, Marin = pretty). But the doll's beauty isn't the same as the angel's beauty, which is where he probably draws some of his regrets since Marin's beauty reminds him of the dolls he loves but he turned Marin into Haniel.
The emotions the characters have are kinda symbolic already; The depiction of love from Haniel to Satan and the mortals to Haniel feels like how Wakana is there in the sidelines while Marin is surrounded by many people getting her attention and not him.
All of this would just be because of Wakana's tired mind and his passion to make Haniel as accurate as possible and maybe exceed the original, especially since he actually sees beauty in the art albeit twisted and very different from how Marin's beauty is and how his gramps (and the hina dolls) show beauty.
Initially, he is actually just trying to challenge himself to create that kind of beauty, cuz that's his goal right? To create beauty that can make you fall in love instantly. He probably regrets that he made Marin into something she's not, since he deformed the type of beauty she already had that he fell in love with. Since at first he hadn't read the source material it was just beautiful, but after reading it he recognized why it is beautiful and what that beauty represents.
Anyway...
This would probably be solved with a simple recognition from the Mandate's author or with Marin's confession.
Wakana doesn't see his work being good enough but perhaps recognition from the author or perhaps even just Marin's words would snap him out of it.
Also,
Marin getting a gig for cosplaying doesn't matter much since she's already a model and she'd still go to Wakana for her costumes unless she is gets into a contract that disallows that. She'll reject it if that's the case and she is just doing cosplaying as a hobby anyway. Also, in the matter of contracts she's probably under the modelling company already, and even if there was no exclusivity clause she would need to deal with a lot of stuff... though her father seems willing to let her do what she wants and would support her... it seems to be more trouble than it is worth to be an exclusive cosplayer for a company. Perhaps part time and with Wakana's help it would be good, since it was Wakana that made a lot of Marin's cosplays. If Wakana gets recruited too then great since he himself is trying to gain more experience, the cosplay company would help in that since it is a different environment to what he's used to. He'd probably even get some custom orders from other cosplayers in there too.
Bruh... my ramblings are too much. It doesn't even make sense and it probably isn't even what Gojou is seeing.
Edit (again***): Yeah... maybe Gojou was just jealous and he doesn't know it, like wanting to keep her to himself. Or he knows a bit. Or he's just having another episode of self doubt.
