Akuyaku Reijou no Okaa-sama

Violet, a viscountess with memories of her past life, was once a Japanese office worker. Utilizing her past life's knowledge in a strangely familiar world, she enjoyed her days. One day, triggered by a certain event, she realizes that she is living in the world of a maiden game she had played in her previous life. Moreover, she discovers that she will become the mother of a future "villainess." The in-game villainess, due to a twisted family environment, ended up committing misdeeds... In other words, the mastermind!?

(Source: Alphapolis, translated)