Yup, someone posted the same issue earlier and he/ she said they were able to get a straight swap for a new device from the Apple Store. Apparently they have a stock in case things like this happen.
Apple should be extra tight with their quality control.
Since you had a dead pixel on your iPhone X, there is a clear difference between a defect and quality control issue. A dead pixel isn't a quality control issue, that's a defect.
A Defect would be what you experienced, a dead pixel or a bad speaker for example on an iPhone is a Clear example of a defect. Not every display would be perfect, because that's what happens when you mass produce an iPhone into the millions.
A Quality control issue would be if you had a scratch on your iPhone, dust under the camera lens cover, or fingerprints on your brand new iPhone. Those types of issues are preventable or should be more controlled during the manufacturing process.