There are countless good books out there. If this one isn't for you, just move on. The heroine grows over the course of the story, so be warned. The male leads from the various worlds are all fragments of one person.
[World One] A seemingly gentle but secretly sinister spiritualist older brother × an innocent, obedient younger sister who adores her brother
Su Qingyu: Turn into a kitty, big bro!
Su Jingchen: …
[World Two] A gloomy, scheming pair of twins × a phantom girl who keeps looping back
…
Although life seems peaceful and lovely (?), behind all that dazzling brilliance lie bloody scars. They are each other's salvation.
Rule-based horror: What's real and what's fake? What's fake and what's real?
In short: If there's no path in this world for you, then we'll carve one out ourselves. We will never bow to fate!