5.0 coyotes had an issue similar where Ford even admitted to hearing the noise. They wrote an official statement to there techs and shops that it's a normal operating sound of the coyote.
https://www.mustang6g.com/ford-offic...haracteristic/
probs something to do with being direct inject. Some guys on those forums were losing sleep over the noise thinking it was their lifters. I'm sure it's just a characteristic of this motor as well. Most modern engines are all noisy.