my Korean employee is driving away customers and i don't know what to do

So this happened recently and I genuinely don't know what to think anymore.

I run a small restaurant and hired this Korean-Chinese (조선족¹) lady as kitchen help. She told me the pay wasn't enough and just... stopped showing up to assist customers. So now I'm basically running the front alone, barely scraping by.

She's 20, graduated from culinary school, so I figured she'd at least care about food quality. Nope. Her taste standards are completely different from mine, she gave up on making the food taste right, and her whole vibe is like. Extremely blunt. No warmth. Think corporate intern energy, not hospitality worker energy.

And customers NOTICED. Middle schoolers, high schoolers, they've all been coming in less. At first I thought maybe they just didn't like the new menu items? Hoped it was that?

Spoiler: it was not that.

When she makes mistakes on orders, customers just... take the wrong food and leave without saying anything. And sales have been going DOWN ever since she started. Like why would that happen if it wasn't her.

I'm genuinely confused. Is it normal for one employee to tank an entire restaurant like this??