Luzy's Manga

After a traffic accident in South Korea, FL reincarnates into a fantasy novel with the goal of returning home to her beloved pets. She navigates the challenges of the "System" and gains strength through regressions, and signing contracts with the constellations, eventually conquering the Tower and defeating its owner. However, a system error sends her to a new fantasy-romance novel as a villain.

FL is strong and cool, while the ML is a power-seeking follower who admires her strength.

MC got reincarnated as Myungha to his friend's novel, has a system which tells him he's going to die in 300 days if he doesn't make Yeowoon happy. Happiness is measured by points.

Myungha: Cool, strong, has a strong will to protect and take care of Yeowoon.
Yeowoon: Cold at first, tsundere, is a track-star runner, poor as heck, family problems.

A man who recently inherited an entire building in Seoul's upscale Gangnam neighborhood must first operate a diner in the same building for five years.
Between 11 p.m. and 1 a.m., ghosts burdened with unresolved emotions visit the diner seeking comfort foods that evoke memories of their past lives.

Throughout his journey, he embarks on several side quests to aid the ghosts in finding peace. It's quite emotional at some parts.