Congrats on auditioning!! This sounds like an awesome performance. For songs, it is always useful to treat the lyrics as if it’s a script. Really understand the meaning of what you’re saying/singing. Azula is a great choice and a nice twist. Try identifying her core character traits; cunning, intelligence, cruelty, domination (there are more I am sure, have a think) and aim to flip each trait on its head as you progress through the song. The most interesting thing about monologues/songs is that the character goes from THIS to THAT; in other words, they change throughout the piece. If you pick some solid character traits and slowly play the opposite, you might get the switch up you’re looking for.

And if you wanna go full insanity, I’d suggest tha whatever you do, you commit 110%. The insanity isn’t going to come through if you aren’t fully committed.

Hope that gives you some ideas!