That's something I've always thought about Kpop groups when going through their music, that their Japanese catalog is usually weaker in song and production quality, almost as if they're leftovers from their "main" Korean discography. I would say NCT 127 has many really good Japanese songs but for example EXO's Japanese releases are significantly less good than their excellent Korean discography.
Do you agree? Is there any group that you think have an outstanding Japanese discography or puts as much effort into their JPN material as Korean one?