Kpop is a highly manufactured industry. This is a well known fact. No kpop fan is stanning a kpop group thinking that their faves are the next Kendrick Lamar. Kpop fans are actually very self aware about what they are in the genre for. Do you think someone who stans Red Velvet is sitting here and pretending that the members do not have a team of songwriters behind them?
With that being said, BTS (and the likes of Big Bang too) really marketed the authenticity schtick to make themselves stand out from the rest of the industry. It's a big reason for their success.