Born year 2000. Wiki says came to NZ at age 14 (from Hong Kong) in 2014, and left age 18 (2018). So based on the above he sadly left a year early.
https://en.wikipedia.org/wiki/Calvin_Harris_(footballer)
If that rule came in before 2019, he might have considered staying, 1 extra year? Even as an 18 yr old he probably realised the chances of playing international football was far greater with NZ, than England or USA.
But being only 1 year short of the above criteria, could he & NZF apply for an exemption to FIFA?