This is sadly always going to be the case I fear. It's always going to be very hard to do all of the contestants justice with the edit.

They've got these hours and hours of footage to edit together into some kind of coherent narrative so they're going to look for threads or storylines to follow. Like the girls who struggle in training, then come good (or not) in performance. They'll get extra screen time and those annoying repeating edits when they hit the high notes or whatever, but a girl who just hits the notes first time, in practice then also on stage, can just get glossed over.

MNET are definitely guilty of some lazy editing and favouritism of some kind, but it's all part of the game unfortunately.