Main dancer doing main dancer things

I can do that in under 2 sec

Completely agree with this. As a dancer myself, I really do think that Yena and Chaewon have better techniques than Eunbi. While they all have their minor issues as well, Eunbi's inconsistency really puts me off. I'd also like to add that aside from what you already mentioned, her arm control is very inconsistent as well which is kind of troubling considering most of IZONE's choreos use that area a lot.