I agree with the DMCA method.
While a plagirism detecting bot might sound ideal, it has a flaw. What if you write on other sites? Many authors post their novels on competing sites before or after coming here.
Note: I'm not a lawyer and you should not take the below information as legal advice.
As for books with the same title, most book titles are in fact NOT copyrighted. It's rare for book titles to have copyrights due to them being short and using common words. Ever read Daedalus? One of the top originals. There's literally over a dozen books on Amazon with the same title or part of he title. Usually only rare exceptions copyright book titles for popular titles. Such as Harry Potter, Lord of the Rings, etc. It's an expensive process, but worth it for books like those.