“I don't know why you want the X button to be this big and this highlighted — you can be much smarter with this X button and still keep it visible but with a different presentation, without the background color.”

Don't make the dismiss X button the first thing a user sees

A large, high-contrast dismiss button primes users to close before they have read anything. The goal is not a dark pattern but a de-emphasized one: remove the background fill, reduce size, or position it where it is findable but not the focal point. Users who want to leave will find it; users on the fence should not be directed toward it.