A few more I don't see listed yet:
Ruler of Your Own World - main character trains at an action school and then goes on to work as a stunt double
Art - drama special about the filming and making of a documentary about a fictional cult classic film (a drama special about a documentary about a movie!)
Uzumasa Limelight - about an actor who is close to retirement, and working in kind of a dying niche (hahaa that pun was not intended and will probably not make sense unless you at least read the synopsis). Setting is kind of specific to samurai movies/TV shows and the like (this is a movie, not a drama, but it's very specifically about a film studio and its actors, so I thought I'd mention it)
And also It's Okay, That's Love's male lead is a writer, but he has a radio show, if I recall correctly
And this one is also pretty in the background, but there's a character in My Father is Strange that works at a KBS-like entity (lol) as a variety show PD who gets semi-demoted and assigned to work on behind the scenes filming of a drama that another character, who's an actor, is appearing on. And his future sister-in-law works as the actor's manager/agency intern