Arifureta Shokugyou de Sekai Saikyou (WN) - Chapter 461

After five years, Ning Xi has returned and is out to take revenge on the sister who turned her parents against her and the childhood sweetheart who betrayed her for her sister. She aims to fulfill her childhood dream and become a famous actress. However, her sister is still out to get her, and she has to avoid all her underhanded schemes.

This stands at the forefront of strategy guides to Life (a shitty video game)!

Born naturally defective but possessed by the spirit of a divine dragon. Inheriting the divine dragon’s will and power, growing scales and magical claws, imperial waters containing the breath of the dragon, travelling through clouds and summoning rain, an invincible physical body. In this world and era, countless men dream of slaying dragons. Li Mu Yang has always lived a hard life.

- Description from Novelupdates

The protagonist, Winnie (文尼), confesses his love to his childhood friend—the princess he’s been secretly in love with for years—but is brutally rejected in public. His heart shatters, he’s humiliated and ridiculed, and he collapses unconscious. When he wakes up, he vaguely remembers his past life’s memories and realizes he has transmigrated into the world of an otome game he played before. At first, he’s thrilled, thinking, “Nice! I must have been reincarnated as a villainous side character who disrupts the protagonist’s romance, right?” But then… surprise! He’s not just the villain—he’s the “Saintess”!