Codmic horror or normal horror recommendations

So I been trying to find a novel or a series that bring the excitement I got from the Southern reach series, Fantastic land, John Dies at the end and blindsight.

I love cosmic horror, but I'm looking for something long that will not be over in a couple hours of diligent reading.

Also, I love the idea of attraction parks gone south like Fantastic land so if anyone as a book they been wishing to recommend please do.