I have generally found that the best children's content all holds up amazingly well when viewed from an adult perspective. Think most Pixar films, Harry Potter, Avatar: The Last Airbender, The Little Prince, His Dark Materials, Roald Dahl and so much more. Great authors simplify complex adult themes for children, but never forgo them.
Raising a simple observation: the distinction between 'children's content' and 'adult content' is a helpful fiction without a boundary. Children's content is really stories about how people should behave, or what situations might arise that they will need to deal with and stories for adults are much the same. Adults aren't more sophisticated than a teenager, they just have better impulse control (which isn't really a factor in consuming stories) and experience (which means they reject some poorly-told stories as impractical but doesn't come in to play with great storytelling).
I'm not sure what kind of life you've lived, or how old you are; but stating that
> Adults aren't more sophisticated than a teenager, they just have better impulse control
is reductionist and absurd.
Some experiences are only available to adulthood. Some experiences take decades to transpire; some experiences need decades to pass after their conclusion before they can be fully understood, contextualized, and woven into one's self.
I know this is subjective, but I'm not sure I agree. Some of the later Pixar films seem to have plenty of adult themes/moments to me. "Coco" (2017), "Soul" (2020) and "Luca" (2021) have things that strongly resonate with me as an adult, while obviously having appeal to kids. "Turning Red" in contrast feels pretty childish, but that's the exception. (Haven't watched Lightyear as the subject doesn't interest me).
