>Again, if you have received an authentic Apple threat notification or similar alert from WhatsApp, Facebook, or Google, [...]

does google (or whatsapp/facebook) actually have similar alerts to apple's threat alerts?

the linked page for google is the typical "sign in from suspicious location" and "unusual number of emails sent", which is significantly different from what apple does when it thinks it detects a nation-state actor using sophisticated and targeted spyware.