A simple trick. Want more 3*s for bluefes? All you have to do is install a bunch of competitor gacha games on your pc.
Nexon's anti-cheat is ring 0, meaning it has kernel level access. Meaning it can see literally almost everything on your pc including your installed games.
When it sees that you're flirting with other gacha games, it dynamically ups the banner rate-up % chance to lower the chances of you losing interest in BA. It's as simple as that.