When I wrote my first novel my characters almost immediately started doing things on their own. Ar first this was somewhat alarming so I searched for interviews with writers I admire to learn about their processes. Specifically Michael Ondaatje and Haruki Murakami. I was happy to find out that both are extreme ‘pantsers*’ as opposed to plotters, yet both weave complex tales with many threads that somehow resolve. I let my characters do their thing and those unexpected actions ended up being important to the complex plot that emerged on its own.
*Pantsers write by the seat of their pants. And Cujo is the book King has no memory of writing because of being drunk and on drugs the whole time. Which he regrets because he likes the book. He is also a pantser!