Sennek is singing way out of her vocal range. I can tell that it's really uncomfortable for her to sing in that part in her register. When she reaches the chorus she needs to shift in her vocal register so that resonance comes through, or else it will just sounds flat like it does now. It was very noticable in the studio version that she was trying her hardest to sing on top of her lungs and using her higher chest voice. If she can't get help from a vocal coach, she should at least sing in her lower chest voice or transition smoothly from her chest voice to head voice and then to mixed voice. Otherwise, the key of the whole chorus needs to be lowered for her. My guess is that Sennek is relatively new to belting and probably isn't very comfortable with the technique yet. The problem with the key of the song is that it forces her to belt out the chorus in her head voice when belting doesn't even need to be in the higher chest voice. This is a very fixable issue, but yet they insist on her singing in a register she obviously is uncomfortable with.