After I Transmigrate into a Book, the Plot Goes Off the Rails

[Two Male Leads + Devoted Couple + One-Sided Mind Reading + Transmigration Into a Book + Happy Ending] #My First Work, with a Terrible Ending. Enter at Your Own Risk, Enter at Your Own Risk, Enter at Your Own Risk# Shen Tinghuan, a workaholic who never took a day off, got his bonus, only to be knocked into a novel by a telephone pole. He became the villainous number-one side character who dies a gruesome death at the hands of the male lead in a story about obsessive love. To survive, Shen Tinghuan obediently kept his head down, but ended up falling for the male lead. The little System turned into a three-dimensional carbon-based life-form, the kind Shen Tinghuan used to despise, and got stuck in the novel's world. Worse, the rival he couldn't stand was plotting to get his hands on him?! Then there was nothing for it but to fight back! Shen Tinghuan returned to the real world and had decided to stay single for life, but then he ran into the man he loved. But why is this love interest such a pain? The groveling tour is ready. Get in there! Content warning: The early part is okay, but the later part falls apart. Don't read it, don't read it, don't read it. If you're stubborn enough to read it, don't complain, don't complain, don't complain!!!