Wangssen01
It will be a very light, sweet romance focusing on Young Severus Snape and an unnamed female lead. Most characters will be bashed and that Severus (and likely others) will be severely out of character compared to canon. It's intended purely for entertainment and escapism.
Born in 1958, Petunia is only two years older than her sister, Lily, but she feels burdened with the responsibility of looking after her. Living in 1960s England, everything seems surreal. The original Petunia yearned for her parents' love, wishing they weren't so biased towards Lily. However, the transmigrated Petunia couldn't care less about that.
After an incident where she jumped into the water to save someone, she fully recovered her memories of her past life and realized she was living inside a fairy tale book. This discovery made everything feel even more unreal. When she learned that her sister would become the mother of the "Savior" (Harry Potter), the boy from Spinner's End (Severus Snape) would be a deeply devoted antagonist, and she herself was destined to be a villainous cannon fodder, Petunia's reaction was essentially, "This setup is great... NOT!"
For her, there's nothing better than navigating this era of economic crisis by relying on resources and money. Petunia has no magical abilities, but her sister and others go off to Hogwarts to study, leading them down completely different paths. As for the wizarding world... Dumbledore... Hogwarts... safety is a major concern. If Voldemort is around, "bye-bye" - she's not obligated to go to that castle.