The original by Robert E Howard, not most of the adaptations or sequels by other authors.

[ ] One of the main recurring conflicts in the original series of short stories is how Conan struggles with understanding social norms, and is often mocked or taken advantage of for it.

[ ] Conan says what he means and means what he says and expects others to do the same. He is often shocked if and when he is betrayed, even if to the reader, it seems obvious that it would happen, because he assumes others will keep their end of whatever bargain he made.

[ ] He can be extremely blunt, which other characters often interpret as him being rude and crude. Characters who spend more time with him often learn that he's just being honest, and doesn't typically mean any harm. In some stories, this is often in direct contrast to "civilized men" who act polite in public, but are actually despicable abusers behind closed doors.

[ ] Conan is highly intelligent. He's a good battle strategist, a skilled thief, learned multiple languages, noticably gets philosophical at times(while insisting he's not a philosopher), and becomes a king noted for his wisdom. Despite this, he's still ostracized, presumed stupid, and looked down on for being a barbarian and not completely adapting to what is expected of him.

[ ] The stories often CRITICIZE social norms through Conan and his adventures.

[ ] There is some speculation that the author Robert E Howard himself may have been on the spectrum. He himself struggled with understanding social norms, was very repetitive with certain aspects of the story, was noted to be eccentric, was bad at team sports but good at one on one sports like boxing, and was highly critical of society as a whole, as well as most forms of government. Conan may have been his self insert he used as an outlet for his struggles and frustration towards how society has treated him.

Any other details:

A couple links regarding the possibility that Robert E Howard may have been autistic (link 1, link 2)

As a side note, a lot of people accuse the series of sexism, but Robert E Howard was actually very feminist for his time, going out of his way to defend the accomplishments of women and trying to incorporate as many strong women as he could. There's a recurring theme regarding women choosing the life they want, and then fighting for it. He actually also complained about his editors pressuring him to write more raunchy scenes because he felt it was taking away from the world building. (link)

He also was very strongly anti-facism despite what a lot of people online claim, literally referring to Facism as, "sordid, retrogressive despotism...slimy...a new fad-name for industrial tyranny"