When you really have done a lot of models on a topic/issue

I’m revising my novel for my agent. Most of my success has been nonfiction, and I tell myself I’m not a good fiction writer. I’ve worked on this thought and other thoughts about my novel so many times that I feel like I’m just spinning. The R-line I want is to send her a blockbuster thriller. Maybe I don’t need to work an unintentional model?

The problem is that I’ve done lots of intentional models, but I’m not getting my desired result. Any thoughts?