You can get magic just by having a normal character in a normal fantasy world. Early 20th century + magic is hardly unheard of as a setting, it’s not like isekai is a requirement for fantasy elements, it’s just a lame justification. I imagine the FPS pro element will come in once Touri gets promoted and can use some of her game-sense to help control the battlefield, which would be almost as silly as becoming an excellent soldier because she was good with mouse-and-keyboard. Best we can hope for is the modern propensity to innovation causing her to use magic in a unique way.
But you could just make her a non-isekai’d character who grew up reading lots of books, or who grew up with a wise teacher, or from a tribe with unusual perspectives. All would be more organic ways to set up this sort of character. The only thing that IRL knowledge is required for is recreating future tech like transistors or nuclear bombs. Which is a shitty trope that gets old fast, and I hate that it’s the closest thing we have to engineering fiction.
