there are different levels of children's media, though. some media aimed toward children does go that deep, because it IS meant to. not every "adult" theme is inherently fucked up or edgy, either. Take Miyazaki works, for example; often there are adult themes of being restless in one place, facing burnout, starting new families, etc. alongside the more child-friendly themes, but there are a lot more of these adult-facing themes in, say, Kiki's Delivery service (progressing onward toward The Wind Rises, Princess Mononoke, and Nausicaa) than there are in My Neighbor Totoro, because children's media covers a wide variety of different scopes. Miyazaki works are also completely different than, as mentioned, MCU, which predominantly targets children for the sake of toy sales, and both of them are also different from other children's media that has different goals.

and this isn't even getting into series like Animorphs, one of several children's series that goes that deep and that rough and that "fucked up" because it recognizes that being a child doesn't inherently protect children from the harsh realities of the world, and because they often need tools such as children's lit with those themes to help them understand the complex dark realities of the worlds they either face every day or WILL face as adults. Animorphs being a series intended for children doesn't erase its themes of the hardships of war and exploitation and other big, real-world issues, and it doesn't make those things any less complex or even less relevant to adults. They may still not be interesting or relevant to you personally, but that doesn't mean that they are all inherently simpler or without any conversation for adults at all.

painting all of children's media as a monolith just isn't accurate and saying that by design it all, uniformly, cannot approach themes relevant to adults as well as the children it's aimed toward kind of ignores a lot of the work that is put in on the production side of children's media.

some adult media is vapid as hell too, so it's not a superiority thing either. Simplicity and complexity can be found in either style of media, because labeling something as "for children" or as "for adults" is still a really broad umbrella encompassing too many different things for you to just say they're all the same.

maybe if you watched more children's cartoons you'd develop an attention span

i'm sorry ayrt didn't cater to your exacting tastes. here, maybe this will suit you more:

fart