Casein the Night Before a Show?

Is it better to just eat a meal of steak and carbs(since I’m carbing up) rather than use casein protein before bed the night before a contest??

I wouldnt be worried about your muscles breaking down overnight the night before a show. You have the muscle or you dont at this point. If anything you are just risking water retention from any lactose or sodium from the casein, stick with food.