You like what you like! There is a lot of schlock superhero stuff, that’s gonna be the norm when the push all kinds of crap.
As far as self contained superhero stories Batman the Long Halloween is a personal favorite. There are 2 more trades that follow it but that stands on it’s own. All Star Superman is one I’d push you to read regardless, I think it’s very important in a lot of ways. Then X-men God Loves Man Kills stands on it’s own. Honestly I’m hesitant to recommend superhero stuff to anyone anymore. I feel like if you wanted to you would of picked something up and tried it on your own.
Beyond that, I’m a little shocked to hear you’re not down with Steve Dillion. I guess it can be a bit acquired but Preacher is a hell of a work. If that’s not your thing, maybe Transmetropolitan would be more your taste art wise? Also in Vertigo DMZ, Fables, Y the Last Man are all classics. Of course thee is Sandman in a class it’s own artists and stories always rotating. Also since you mentioned Watchmen, V for Vendetta is the sister book in my mind. Also far away from any of that, and something that’s more slice of life/using comics as a medium in a fascinating way is DayTripper
which forever reason is the main book is this diatribe I’d recommend to you, buried in the middle here
Have you looked into the Image stuff at all? A fair amount of artistic variety among sci-fi, crime, and horror stories there.
Beyond that I don’t know if you’ve checked out any Will Eisner Stuff. There’s also a translated comic called Okko that I think would be your speed, it’s very pretty.
**edit- BTW @mothmanspirit I love the bits you’re writing here for manga I’ve never heard of, keep it up it’s always appreciated. And while I have nothing against Old Man Logan it’s hardly a golden gem either.