It is extremely unlikely that your iPhone 14 is new. The battery health of 88% that you posted is far below expectation.
Apple stopped deliveries of the iPhone 14 in February 2025. So, even if you got one of the last iPhone 14's off the production line, your iPhone was sitting in a warehouse somewhere for about 18 months before you purchased the phone.
That would have been terrible for the battery to sit idle for so long, but it would help explain the poor Battery Health.
Tap Settings > General > About and look for the Model Name of your iPhone. What is it? Does the Model Name start with a number? If yes, what is it?
Now Tap Settings > General > About and look for information about Warranty and Service. What do you see? Do you see "Coverage Expired"?