Comps don't have to include books that are about the same topic. They can be books that use a similar structure, deal with a similar family dynamic, address similar social justice issues, etc. I have three very different comps I'm planning to use for my query for my novel. One is a nonfiction book about the same subject. One is a novel that addresses similar issues of social justice but is more literary in tone than my book. And one is a historical novel (like my own) that has similar family dynamics, although my book occurs in a different period of history. All of these comps have been published in the past five years.
I would search for comps on Goodreads where you can find good descriptions of the stakes and structure that might parallel your story.
And here is my general understanding of the various genres you listed:
Literary fiction is focused on language and character development, with the plot being secondary. Think beautiful, poetic, or even experimental writing with complex characters.
Commercial fiction is a broad category that encompasses most major genres, including mysteries, thrillers, fantasy novels, etc. Think fast-moving plot with lots of twists and turns. The writing is competent but not soaring, and the characters have interesting backgrounds. Commerical fiction shows up on the stands in airports when people are seeking an easy, engrossing read for their flight.
Upmarket and Book Club are interchangeable terms. They refer to fiction that is more character-driven with an emphasis on good writing but not as focused on the beauty of the language in literary fiction. These books often address interesting moments in history, political subjects, unusual historical figures, eccentric characters, etc. Their stories revolve around a theme that invites discussion. For example, The Four Winds, by Kristen Hannah is book club/upmarket. She's a strong writer, her characters are intriguing, and the story takes place during the Great Depression. The theme of the book revolves around the exploitation of farmworkers in California and their struggles to unionize. For a book to fall into the category of upmarket/book club, it should have big ideas and themes, and the writing should push toward being literary. A lot of book club books fall into these genres: historical fiction, women's fiction, social justice, and memoir.
Hope that helps some.
JeanneG
