It's common knowledge when K-pop groups sing in Japanese they market to Japanese audience only.
Most K-pop songs that are market for everyone seems to have many English or sometimes Spanish mixed in. What if Korean language becomes minority in K-pop ?
Edit: I'm talking about songs from 2020 to 2022+ present all have some English. Ever since BTS sang it's songs in English , Blackpink and Twice did the same. NCT 127 was the first one in 2018.