How can I alert Apple about spyware targetting Apple users?
For what it's worth you can reach Apple's legal department through the contact form on https://www.apple.com/legal/contact/. Picking "Phishing and Spam" from the drop-down leads you to https://support.apple.com/HT204759 which, among a lot of useful info on how to protect your devices, lists a number of options on how to reach out to Apple in these cases.