Yeah, please don't put them in some East Asian bracket. All of them have different cultures, different strategical interests and different histories. Don't try to own "East Asia".
Both are under US security guarantee, remember that. No matter how hard some Chinese clones try, it is only a matter of time before they become friendlier.
The Koreans in general hold a more negative view of
China than Japan. South Korea is entirely aligned with the Western style of polity, not to mention the alignment with the US.