yeryry's question above is very interesting but yet unanswered.

As far as I understand, we are Ok to keep Japanese movies/TV dramas soundtracks as long as main composer has VGM/anime works here but not western movies. So, why then https://vgmdb.net/album/98468 is allowed? It's a western movie, so it should be deleted, no?

Then, onto yeryry's question. Koji Makaino, Tetsuya Komuro, etc... to name a few have tons of mainstream music in their works; in fact, much more than their anime/game works. Should we allow these works? It's not western mainstream music, so it should be ok, no?

Or the true reading of western mainstream music is any mainstream music? Then can we consider removing "western" here?

Then I would understand that "Oppai Volleyball" OST is allowed because main composer has VGM/anime OST in his discography but that we discard, let's say, Tetsuya Komuro own solo albums because it's neither related to category 1 and/or 2 even if he has works on anime OST.

From the time being, I feel Category 3 and 4 need to be more detailed or given some examples. I still not feel comfortable with them.