You know a little detail I love in The Martian book? That Mark is obviously smart, but to different degrees depending on the subject.
He’s a mechanical engineer and a botanist. This makes him especially good at math, biology, food science, physics, and techy stuff that involves building things or taking stuff apart and making it do something else and general problem solving
He’s also generally good at chemistry. He knows that to make water he can breakdown hydrazine, but doesn’t think about the fact that it would cause the place to fill with hydrogen and almost blow up until it does. He also knows you exhale some oxygen each time you breathe, but doesn’t know how much.
He knows that solar panels are held at a 14 degree angle but doesn’t know why, and only knows the angle because he was in charge of setting them up
When he gets injured he doesn’t say what muscles, just that his back hurts. He fixes most of his muscle injuries with pain killers and warm baths while thinking about how the medic would have more detailed instructions
He has no idea how the pilot is so good at pilot stuff, and never differentiates different kinds of rocks like the geologist would
It’s just cool to have a smart character who is smart at things that make sense for their degrees and experience. So many characters get the Sherlock Holmes treatment where they’re good at whatever the plot needs, but in this case the book uses his blind spots as part of the plot. He knows enough chemistry to solve problems but not enough to anticipate the problems the chemistry would cause as well. It’s refreshing to have a book where what a character is bad at, or just not super good at, works with the story rather than just getting glossed over or having the character magically good at everything because if you know botany obviously you also know anatomy and geology and meteorology, etc