There are two major things going on with the character. First he is growing up and transitioning to being an adult so there are some of the typical aspects of that age. The second part which is sometimes overlooked is his trauma and how it is also impacting his transition to adulthood.

AFAIK, Salinger started creating the character before the war but then while recovering from his own PTSD during the war he wrote more of it. So the character is a mix of this rebellious youth character and a character living through loss and trauma. I think there is a lot of Salinger in the character especially a lot of his fears about himself and his own capacity to deal with his trauma.

The entire outlook of Foundation is that it has a different look at what really matters in history and the outcome of the story beyond the individual. This is generally in contrast to a typical fictional story or even how we often tell our history which looks at individuals and their impact and importance. I think this way of thinking is actually becoming more relevant in modern story telling and history. Even if they still hold to some of the traditional story telling traditions of focusing on individuals.

It is unlikely Asimov gets this story written without being a known quantity. It is unusual. It isn't going to necessarily appeal to a broad audience. It is a classic in literature in large part due to the way it breaks from traditional story telling molds. Things are not classics because they are for everyone.

Pennyworth is one of those shows that is somehow extremely entertaining while also flaunting how ridiculous it all is. Hard to say it is "good" but it is enjoyable.