Three things.1) SE is a business and needs to make money. 2) I highly doubt there’s a big enough demand for this glam to warrant the resources it would take to design a boss fight for it to drop. 3) I don’t think you have an understanding about what f2p Korean games offer for sale. They make their money offering stuff like characters, gear, and enhancements to grown the player’s roster. If SE ever tried to offer stuff like real gear with real stats that top what’s already available the community would be out with pitchforks