I have two. The Ritual and Drowning.
The Ritual is pure smut. 61 chapters and every one contains a graphic, demeaning sex scene. I’m convinced the author was an adult film screenwriter and decided to try their hand at writing a novel. There isn’t a single likable character in this book.
Drowning isn’t a great work of literature. I felt that the characters were very two-dimensional. I hated how naive the author made the protagonist. It made me have a lack of sympathy for her. The ending was series finale of Dexter bad.
For me it was The Atlas Six. I could not get through it. The writing was one thing, but the constant jumping back and forth between 6 POV was too much. I made it 70% of the way through and went online to read how it ends. Was not impressed so I DNFed it.