not to discourage anybody but writing a novel is never just the shitwork of producing a large number of words. imho if you're not also bleeding from the eyes, crying, lying on floor in foetal position etc, in attempts to produce excellent prose, you need to introduce that into your routine

But is this all caused by the prose part? What about the story and the structure and the way events come together?

Interaction of forehead and plate glass window often integral to the process too.