You need to pare down the premise to find the center of your story. For example, the inciting incident is probably not the singer’s fallout with her old band, but the signing of the contract with the mobster, who by the way will be either a “promoter” or a “producer” and, for an unknown singer, definitely not a CEO.? As for the tragedy, be more specific. Different people have different understanding of what constitutes a tragedy. Did the promoter have the ambitious singer’s competitor/friend murdered to smooth the way for her rise? Or does the promoter pump her full will drugs during her rise and leaves her in the gutter, having stolen all her money?

Deborah_b suggest concentrating on the rivalry. If you want to go that route, you need two strong characters. The singer you have as the MC and one in the old band. In that case, the promoter’s role will be reduced and could probably be left out of the logline in favor of some information about the rival.