Cane someone help me pick a book for my little sister

She’s 15 years old and the kind of books she likes are six of crows, Sherlock homes, a good girls guide to murder, shadow and bone, inheritance games, etc (mystery/thriller) I’m pretty sure she’s read the more popular ones but her birthday is coming up so I wanna get her something she likes preferablely a solo book with a banger of an ending (nothing too depressing) and please as PG as possible, my mum is hyper vigilant about these things…. She doesn’t like sci fi and not big on fantasy or dystopian