Not awakening doesn't mean she doesn't have any powers, It means that she won't have control over the powers she'll get and that it would be easier for another demon to steal her powers and declare themselves the demon king. This was kind of explained on the first couple of chapters
Not only that. Her powers are threatening her health. You know the fever and coughing up blood. As an awakened demon king she won't get killed by her own powers going out of control.
shes already destined to become the demon king, what she wants is to be able to control her powers. if she cant, then either someone will slay her (she thinks either lacius or her dads, but therell probably be a third party going for her head), or, because shes half-human, she wont be able to contain all the demonic energy and itll kill her. so her options are either become a master, all-powerful, fully awakened demon king or die :P
I only read a little bit but why she so bent on awakening as a demon king ? like uk the ending so I’m confused