music
I bet you're not into both countries' music. I regularly go to local music festivals, and the hidden highlights have always been Japanese rock musicians. Japanese Rock musicians are good at playing instruments because they have their own 'Band' culture. But South Korea doesn't have a similar culture based on their zero sum education system and autistic Apartment culture.
Korean bands and Idols are shit at performing in music. Koreans only outperform in some dance things.
And Japan has many serious, famous, critically acclaimed musicians, even the notorious noise music musicians like Merzbow are Japanese.
Gamess
There's no need to elaborate. Korean games have emphasized too much on making money. So Korean game companies have become the center of trash gacha games.
Anime
Anime deals with the universe, irony, world while Korean dramas deal with copied and pasted simple love lines.