I think that's more to do with the writing quality than anything, really. As you've said, there's Shonen stuff that isn't just generic Highschool drama stuff, like HxH and JJK as previously mentioned, but I tend to enjoy Seinen more than the average Shonen because the themes and settings are more relatable to me as an adult.

~~And I'm not going to lie, I kind of have a guilty pleasure for some edgy stuff every now and again.~~