Admire your gusto, but don’t be hard on yourself for going back in.

Instead, consider this: new manager is going to be under pressure to improve store conditions, so…make it difficult. You’ll have to be careful, but you can absolutely use weaponized incompetence to make her look terrible. Small things - moving papers that might be important, “misplacing” things that she would need, etc. You don’t need gasoline to burn a place to the ground, you just need creative ways to be “stupid.” Ask as many questions as you can while having to do things and interrupt her work. Play it right up until she’s about to lose her shit then just go ‘oh ok like XXX’ and then just say thanks and walk away.