Fanservice Paradox I Only Like Your Character Settings! You can try using the keywords "showbiz", "singers", "dancers", or "music" to find idol stories, or just straight up combine two to three tags like [singers and dancers and music].
"For My Healing Life" an Idol BL Harem but there hasn't been an update for a long while. If you're also interested in main lead as an actor. Try "I Ship My Adversary x Me" and "How to Say I Love You" both the MC and ML are in entertainment circle.. "Kill the Lights" the MC transmigrated into an actor..
Rebirth of a Movie Star Superstar Aspirations Top Management King of Classical Music Rebirth of a Supermodel
its a manhwa but Youre My Idol Hyung is about a maknae who got into reading shipping fanfics of him and his members. the plot develops from that
Well it's not translated yet but it has what you're looking for though mostly they are actors: I Became Popular After Being Forced to Debut in Metaphysics (被迫玄学出道后我红了) - it's about a supernatural variety show (well there are idols who joined in this variety show) Dark Guard Leader Makes His C-Debut (暗卫首领C位出道[古穿今]) I Became Popular After Dating My Ex On a Variety Show (和前任上恋爱综艺后我红了) After the Whole Family Wore Books and Became a Big Bosses, I Became Popular (全家穿书成大佬后我爆红了) - ML is an idol
The Villain Just Wants to be a Salted Fish Male God is Chasing My Brother Your Memes Are Better Looking Than You