The Fed Up Office Lady Wants To Serve The Villainess summary:

A heart-pounding reemployment(!?) story between a fed-up corporate slave and a cold, callous, villainess!Three years after graduating college, Natori Midori, who once idealized the "grown-up adults" she saw as a child, is working hard at her job as a temporary employee. However, one day, her contract is suddenly terminated for an absurd reason. As she sits there, wondering if there would ever be a workplace for her to devote herself to, her phone flashes and she finds herself in the world of the novel RPG she was playing. And before her eyes is the villainess, Lapis Tenebrae, who betrayed the heroine and committed countless atrocities before losing her life!