How do you answer honestly about a technology you haven't used in production?

I name the boundary and move on to the problem. For example: “I haven't deployed ECS myself. I've worked with Workers and queues, so I understand the need for a separate worker, durable state and protection against repeats. I'd have to check ECS configuration and permissions in the documentation.”

That doesn't pretend to equivalent experience, but it shows transferable knowledge. I can ask about the requirements and propose a way to verify the risk. You don't need to know every parameter by heart. But you do need to tell knowing the principles apart from deployment practice. If practical AWS is a requirement for the company, it may remain a real gap — a clever phrasing won't hide it.