1. If you see The story mapping,it appears that the character of the female lead of Yong Pal has become the antagonist of The K2 .Both were corporate heirs and very ambitious and were pitted against their brothers 

2.  you also have Cloud 9 in The K2 which has similarities to the system in Yong Pal

Any thoughts?

I don't think it's a sequal. But i I can totally understand why you would think so, the narrative has somewhat the same pathway/vibe because of Writer Jang. So it is not a coincidence.