One possible scenario in this fanfiction could be that a de - aged Tony Stark brings a new perspective to the events of Civil War. He might be less jaded and more idealistic, trying to find solutions that the older, more conflicted Stark couldn't see. Maybe he forms unexpected alliances with other characters based on his fresh outlook.
In some fanfictions, Zemo - the one who originally stirred up trouble in the movie Civil War - could still be a major antagonist. He might target Peter specifically to get to Tony or use Peter's inexperience against the heroes.
A fanfiction with Tony Stark having a heart attack during Civil War can open up numerous storylines. It could show the reactions of other characters like Pepper Potts, who would be extremely worried. His fellow Avengers might put aside their differences temporarily to ensure his survival. Also, it could lead to a deeper exploration of Tony's health issues that were perhaps overlooked before the heart attack, and how it affects his future decisions in the ongoing conflict.
One plotline could be Peter struggling with choosing between Tony's side and his own moral compass. Maybe he tries to find a middle ground to keep his relationship with Tony intact while also doing what he believes is right.
Often, their relationship is tested. Tony's involvement in the Civil War can cause stress between them. Pepper might worry about his safety and the moral implications of his actions.
One idea could be that Pepper tries to mediate between Tony and Steve during the Civil War. Since she knows Tony so well, she might be able to find common ground that others can't. Another could be Pepper getting involved in the fight herself, using her business acumen and strategic thinking to help Tony's side. Maybe she discovers a hidden plot that could change the course of the war.
The de - aged Tony could also form a mentor - mentee relationship with a younger Avenger. He has the knowledge and experience of his older self but the energy and fresh perspective of his de - aged self. This relationship could be a key factor in how the story progresses, as he imparts his wisdom in a different way and the younger Avenger helps him see things from a new angle, which could potentially change the course of the Civil War in the fanfiction.
Well, perhaps Tony Stark time - travels during the Civil War to a moment when he first started developing Ultron. He then uses his future self's wisdom to avoid creating Ultron in the first place. This would change the entire dynamic of the Civil War as the destruction caused by Ultron was a major factor in the public's distrust of the Avengers. He could also time - travel to meet a younger version of Captain America and try to understand his point of view better from the start.
One possible plotline is that Tony's heart attack forces the Avengers to take a step back from the Civil War. They might start to question the purpose of their fighting when one of their own is in such a critical state.