Apple has a public API with some rate limiting that returns a link to the preview audio file, see:
https://itunes.apple.com/us/lookup?id=1023678453 (https://www.chrisjmendez.com/2017/06/19/working-with-itunes-...)
So probably all that is required is a couple threads downloading and a proxy service with a large pool of IP addresses randomly rotating on every request. Maybe OP also found an undocumented API endpoint somewhere that was not rate limited.