In fanfiction, Harry Potter's magic would be a constant struggle in Muggle high school. He might have dreams about using magic to solve problems like getting out of a boring class or impressing a girl. But he'd know he couldn't. It could also lead to some comical situations, like when he absent - mindedly tries to levitate his pen in class and has to quickly cover it up as if he was just reaching for it.
Harry's magic could actually give him an edge in some ways. He might be able to use his quick reflexes from Quidditch in gym class. And his knowledge of potions could make him really good at chemistry, even if he had to pretend he was just really interested in normal chemical reactions. But it would also be a source of stress, always having to hide it.
In fanfiction, if Harry Potter goes to Muggle high school, it could be a chance for him to grow in a different way. He'd have to rely on his non - magical skills. Maybe he'd make some really good Muggle friends who would accept him for who he is. He could introduce them to some of the less dangerous aspects of the wizarding world, like Bertie Bott's Every Flavor Beans. It would be a whole new adventure for him, away from the usual wizarding threats.
His magic could give him an advantage in intelligence - gathering. For example, he could use a spell like 'Alohomora' to open locked enemy files or doors without leaving a trace. Also, his ability to apparate (if he could find a way to do it secretly) would make him extremely mobile on the battlefield. But he would have to be very careful not to be caught using magic, as it could lead to chaos in the Muggle military world.
His magic would give him an edge in many situations. For instance, he could use the Accio spell to quickly retrieve important items during a mission. However, he'd have to be careful not to expose magic to the non - magical members of the special forces. He might use it sparingly, only when it's a matter of life and death.
His magic could make the Queen see him as a valuable asset. She might rely on his magical abilities for protection or for solving problems that normal means can't handle.
His magic might be a bit off. Since he can't see clearly without his glasses and is drunk, his concentration would be severely affected. Magic often requires focus, so he might accidentally cast spells wrong. For example, he could try to cast a levitation spell on an object but end up making it explode instead.
He'd adapt slowly. His experiences at Hogwarts would both help and hinder. He'd have to get used to the lack of magic in the open. But his skills in dealing with different personalities, like those of his Hogwarts classmates, would be useful. Maybe he'd start by finding common interests with the students, like a love for books or adventure.
The stilettos could slow him down during his adventures. He wouldn't be able to move as quickly as he usually does in his normal shoes or boots. This could put him at a disadvantage when facing danger, like when running from Death Eaters.
If he transfers, his relationships with his Hogwarts friends would be greatly affected. Hermione and Ron might feel betrayed or worried about him. They might try to convince him to come back. His relationships with his teachers would also change. Some teachers might be sad to see him go, while others might think it's for the best.
Well, he'd probably be a bit of an outcast. I mean, he has all this knowledge of the wizarding world and magic. At Muggle school, that doesn't really count for much. He'd have to hide his identity as a wizard too. And think about the subjects - no Potions or Defense Against the Dark Arts. Instead, it's all Math, Science, and English. It would be a huge adjustment for him.
In fanfiction, Harry Potter might struggle in the Muggle world at first. He'd be used to magic for so many things. For example, he might find it really hard to do his homework without the help of magic. He could also be constantly worried about accidentally using magic when he's frustrated, like making his Muggle teacher's chalk fly across the room.