The difference between children and adult media can be tricky to pin down. I don’t have all the answers myself but if there’s one difference I generally (not universally) think works to show it is how the characters are portrayed.
In media for children or teenagers, there is a concern of making your characters likeable. They're certainly flawed and allowed to make mistakes, but never anything too bad that would risk losing the audience’s attention. Don’t go too far or otherwise people might end up hating your characters for one reason or another. Good guys are good, bad guys are bad, there’s stuff in between, but generally if a character is on “the good side” they can’t do anything too awful or the audience is wondering why the main characters put up with them.
In media for adults, there isn’t as much of a concern whether a character is likeable or not. Oh sure there’s still boundaries, but there’s more faith in the audience to get invested in the story due to finding characters complex or interesting even if they sometimes cross a moral event horizon or are just jerks. Adult media tend to operate more on shades of grey and it’s characters usually reflect that by not being stuck purely as good or bad, just being people. Usually. Sometimes “adult media” can be more immature and stupid as kids media of course. Still this comparison seems useful.