Rachel's problem isn't that she's getting ideas and help from Marie, but that she takes credit for the ideas herself. It's the job of a good boss/manager to get talented people and experts to do work they're good at and to delegate and organize the tasks properly. For example, the President of the US doesn't need to be an expert in every field, but he needs to be able to call upon experts and talented people and to use their information to make good decisions.
If Rachel stuck to doing that without trying to steal credit, then she'd show that she had the ability to be a good Empress. Unfortunately for her, she's too busy trying to take credit for these ideas that she's lied to the ML repeatedly.