I would liken the GdT Hellboy movies to, say, the Burton Batman movies in that regard. Hellboy is a Hellboy movie directed by del Toro, in the way that Batman is a Batman movie directed by Burton. Hellboy II: The Golden Army is a del Toro movie that happens to star Hellboy, in the way that Batman Returns is a Burton movie that happens to star Batman. And it should be stated, I really, really love both The Golden Army and Returns.
I adore del Toro's take on Hellboy in general across both films, and would have given anything to get one last movie to end the trilogy and see his vision through to its ending. I'm also a very big fan of what I've read of Mignola's comics, and I'd be down to see a more accurate take on Hellboy brought to life on screen (the 2019 film... wasn't that, imo, and I still think a proper comic-accurate take should be animated), I just wish we could have gotten to see del Toro finish up his story before moving onto a reboot.