JayJayTak's Manga

went to c42 -
Isekai aspect was just to draw you in, since it was only utilize for less than 10% of the story.
This is more of a Mary Sue highschool romance with a wishy-washy female lead with two competing male leads.
There's no sense for setting this story as an isekai as it seems to be the popular story hook to just draw readers to this. She does nothing with her knowledge, she actually seems to be acting like a 15yo instead of a 30yo business owner.
You could literally set the story in 1850's English monarchy with this FL having different fashion ideas, and mother would have told her what happened during her school years, and FL decides to go to the rich academy.
I don't know how she has all those different school clothes since that one ball gown took all of her study time, and she clearly isn't shown making other clothes, or purchasing them. She was also wanting to get a job to help with expenses, but that idea didn't go through.

Read this if you want that mary sue highschool academy life love triangle that focus on "woe is me, I think I like you, no, maybe you".