Get a first draft done so you can type “the end” instead of getting stuck halfway through and never finishing it. You can always go back and fix what you’ve written. But you can’t fix a blank page.
You want to get published? The first rule is, don’t bother writing the book of your heart. Write something’s that commercially viable. If you manage to combine those two and do it well, congratulations. You might become a best-selling author in record time. Or…you might not.
You might think there’s a lot of genius involved in writing fiction, but if that were true, it doesn’t explain why there’s so much writing that just isn’t that good. Unless there’s a new definition of genius of which I’m not aware.
But at the same time, if I never sold another thing, would I keep writing? Yes, of course, because if I give up, then assuredly I won’t sell anything else.