Agreed that Sarah seems too self-aware. I like dry and self-deprecating humor, but it's too much with her. Her "low self-esteem" and constant doubting starting to become a real drag during this episode, although I realize a lot of that falls on the editors/producers for focusing on her.
I'm actually on board with LCK as a concept the more I think about it, although I initially had my doubts. If you can get sacked for arbitrary reasons during the competition (ex: S12's very first challenge, the mise en place race) I feel like LCK is somewhat of a nice equalizer.