Within a genre or subgenre, there are different styles and types of books. The difference can be the sensual/sex level, the romantic level, the amount of plot and characterization, scientific level, adventure levels, worldbuilding levels, etc., etc.
These differences often mean that one reader will like certain books but not others within the same subgenre.
In your own reading, you have probably noticed that you gravitate toward certain writers, and others leave you cold.
I have a question for you, and I want you to think really hard about it.
Can you name several authors or book series that you want your books to be like? I'm not talking subject matter, I'm talking the whole feel of the books.
Why are this question and its answer important?
Novels don't exist in a vacuum. Your novel will not only need a publisher to publish it, you'll need an audience to write to. And despite publishers saying they want different, they want close-to-the-same different, and readers are the same way.
You absolutely must have an answer to this question before you begin to market your book to agents/publishers/readers.