What manga was this?

I was talking to a friend about this manga that had an absolute insulting end, I tried looking for it in my "already read" list couldn't find it! It's pretty niche so maybe someone will know about it?

- Protag is a highschool girl, not popular, she enjoys the idea of being a side character (pretty sure this was a big thing to her)
- A popular girl at her school bumps into her on the staircase, a magic circle appears under them and they are both teleported to a magical world.
- Both are said to be the saintess(? Not sure about this) though everyone picks the popular girl over the protag. Protag is fine with this (I think?)
- Protag's holy powers are stronger than popular girl's (but then it later turns out there was some weird-ass twist about both of their powers)
- Pretty sure Protag's powers are used by her imagination w/ using her gamer knowledge. While popular girl's is something similar but to a lesser extent(?)
- Popular girl has a harem of men basically, everyone treats protag like shit
- Protag studies underneath a grumpy man (who falls in love with her at the end of the story)
- After some conflict and the solutions and the like, Protag is forced(?) to return to her world.

aka protag just gets thrown around then finally tossed into the trash while popular girl gets what she wants.