One possible plotline could be Yor dealing with her pregnancy while still trying to keep her assassin identity a secret from her family. She might struggle with the physical and emotional changes that come with pregnancy while also maintaining her cover.
There might not be a lot of publicly known 'pregnant Yor Forger fanfic' readily available. You could also try joining some Spy x Family fan communities. There, fans often share their own creations or know where to find unique fanfics. It's possible that someone in the community has written or knows of such a story.
A more complex plot could be about Yor dealing with the physical and emotional changes during pregnancy in a world full of danger. She might have to rely on her own strength more than ever, and her pregnancy could even be a target for her enemies, leading to a high - stakes story.
Stray Kids, on the other hand, would also be very concerned. Bang Chan, as the leader, would take charge. He might start asking questions to figure out what exactly happened. Felix could be bringing water or something to make Y/N feel better. Lee Know would be standing guard, making sure no further harm comes to Y/N while they are in a vulnerable state.
Y/N should have their own goals and dreams. If they're interested in becoming an Auror, that can shape their actions and decisions. Their reactions to Draco should be based on their personality. If they're a shy person, they might be more hesitant around him. And make sure their dialogue is natural. Don't make them say things that are out of character just to move the plot along. For instance, if Y/N is a studious type, they're more likely to talk about books or spells when interacting with Draco.
They might immediately stop the concert. The members would be really worried. For example, Jin could rush over to where Y N is with a concerned look on his face. He might ask the medical staff what's wrong and offer words of comfort.
Avoid the typical 'pregnancy is all sunshine and roses' trope. Show the real challenges Yor might face, like morning sickness while on a mission or the fear of not being able to protect her unborn child.
It could also be related to the internal politics within the entertainment industry in the fanfiction. There might be some higher - ups who don't like Y/N's presence around BTS and Stray Kids. So, they arrange some difficult situations for Y/N which end up in Y/N getting hurt. For instance, they might give Y/N impossible tasks to perform and when Y/N fails, there are severe consequences that lead to their harm.