@cryum
You know how like in lot of these game novel type stories, it's filled with 1D characters and the isekai person is the only one with any sort of reality to their character?
From reading the novel, I got the impression this story takes the above and inverts it. All the background characters acquired 2d persona while the heroine, the main leads and the villianess is 1d.
She does evolve though because of the situation they are in. As does the "supporting character." The dude has his own navitity that he needs to evolve out of.
This story is focusing on the people that got tossed away by the reincarnated isekai heroine. That's the impression I had until the author decided to make something more of the villianess.