I wouldn't describe Demon Slayer as a masterpiece. It's visually stunning, not only in terms of the artwork, but also the animation and cinematography. It has spectacular sound design, in terms of its soundtrack, its ambient sounds, and its effects work.

But its writing is a haphazard mix of shounen and seinen tropes that ultimately leave its story boring and predictable and its characters drab and one-note.

Granted, I only watched Demon Slayer through Mugen Train, maybe it gets better after that?

Attack on Titan stands out on OPs list as a show that has all of the same issues. Both were really fun to watch for a bit, but ultimately failed to hold my interest.