Well, it could be driven by his sense of guilt. Thor might feel guilty for not being able to prevent Ragnarok completely, or for not saving more of his people. This guilt could eat at him to the point where he contemplates suicide.
In fan fiction, Thor's suicide attempt could be due to his isolation. He's a god, and being a god can be a very lonely existence. He may not feel like he belongs anywhere, not fully in Asgard anymore and not entirely on Earth either. This sense of not having a true home could push him to such a dark thought.
Another factor could be his loss of purpose. Thor has always had a clear mission, whether it was to protect Asgard or the Nine Realms. But if that purpose is suddenly taken away, like if Asgard is destroyed and there's no clear way to rebuild it or his role in the new order is uncertain, he might feel so lost that he considers ending his life.
Chapter 839, "Because There's a Good Show to Perform", is the clearest early answer because it turns Shi Lei's situation into a concrete plot event.
Chapter 649, "Where Did the Wild Wolf Come From?!", is the clearest early answer because it turns Shang Shuyue's situation into a concrete plot event.
Chapter 486, "So It's All Set Up, Right? Then She Will Set Up Too!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Hearing Jiang Li's words, the audience in the live stream was also...
Chapter 567, "Distant Nephew, Long Time No See", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event. The chapter turns that into something concrete by moving from After separating from Jiang Li and the others, Team L headed in the...
Chapter 656, "If he's the grandson of the richest man, then I am the richest man!", is the clearest early answer because it turns Jiang Li's situation into a concrete plot event.
Chapter 852, "Could That Be an Aphrodisiac Spell?", is the clearest early answer because it turns Xu Ning's situation into a concrete plot event. The chapter turns that into something concrete by moving from Rong Junsheng's words startled Shi Lei and Rong Kexi.
Chapter 778, "The Gift of Being a Director", is the clearest early answer because it turns Ling Bei's situation into a concrete plot event. Early on, Shiguang, I really misjudged you, you're actually this kind of....
Look to Chapter 8 for the clearest answer. It begins with The resentment that had barely calmed among the crowd surged back two..., keeps building through Some of them were relatives of the Jiang Family, who felt it improper to..., and lands on Other people with a handsome and charming appearance.
Chapter 643, "Jiang Li Dominates the Trending Searches!", is the clearest early answer because it turns Trending Searches's situation into a concrete plot event. A useful checkpoint is the way the scene starts with Qi Tianyu joyously carried his construction to the side to wait for...
Chapter 562, "So You Are Not First, But Last?!", is the clearest early answer because it turns Jiang Cheng's situation into a concrete plot event. The chapter turns that into something concrete by moving from After they finished preparing the fish, Guo Xing and Luo Xuan got...