It’s a largely meaningless distinction, IMO, and your example of THE BOYS kind of illustrates why. Yes, it’s a story with a beginning, middle, and end, but it was told in a serialized format over the course of a decade. If that’s a graphic novel then why would the Triangle Era of the Superman books (which ran for about the same amount of time and bookended big reboot-adjacent events) qualify?

More often than not, a collected edition of serialized comics is formatted in such a way as to make it a satisfying stand-alone read, because the bookstore market has become an important piece of the publishers’ business model. If it’s self-contained and satisfying in its own right, but sets up the next installment with a cliffhanger, how is that different from any other book series?

Palmiotti and Gray’s ALL-STAR WESTERN is one of the best DC comics of the last 20 years and the run had a definite beginning, middle, and end — but the ending was only something they came up with when the book was cancelled. It would have run forever if it could. How do you evaluate that?

The original sin of all of this is going back to the ‘80s and all the initial “POW! Zap! Comics aren’t just for kids anymore!” headlines. Legacy media and educators weren’t comfortable talking about WATCHMEN, MAUS, and THE DARK KNIGHT RETURNS as comics (which they are) and applied the “graphic novel” label to those works based purely on vibes. Comic fans and publishers, desperate to be taken seriously, embraced the approach.

WATCHMEN and DARK KNIGHT were both pitched as stand-alone works that could functionally viewed as a graphic novel, and only published in serialized form because of the demands of the industry. So how does that factor in? On the other hand, both of those comics are very formally complex, and so they undoubtedly made changes to accommodate the serialized publishing format, fundamentally changing the end product in a way that would not have happened had the books been released in a stand-alone format. The medium is the message.

If I were to care about the distinction — and, broadly speaking, I don’t — I would argue that only books whose original presentation was as a singular work are “graphic novels” and anything that was originally serialized is a “collected edition.” The fact that doing so would remove WATCHMEN, SANDMAN, KINGDOM COME, and other similar stories from “the canon” is illustrative of how meaningless the distinction is. If you disagree, that’s fine, but at some point it’s just Cherry-picking. If anything “credible” is a graphic novel and anything “frivolous” is just comics then you’re giving away the ruse.

(Not you personally, I’m speaking in general terms.)

Ultimately, comics are the art form. Graphic novels are a product category. As such, the sellers reserve the right to define the term. HUSH and THE DEATH OF SUPERMAN are serialized comics stories that were conceived and structured as graphic novels, but are part of never-ending, ongoing comic titles. They were “collected editions” until their cultural cache and sales numbers transformed them — as if by magic! — into graphic novels.