How to find my stolen iPhone?

If the thief simply erased it by restoring it in iTunes or finder, then the remote tracking link is broken and you will not be able to track it with Find My. Nobody needs to hack anyone’s AppleID to remove a device from Find My. They just need to erase the device.

As long as that device remains listed under your AppleID trusted devices (https://appleid.apple.com/) then activation lock will prevent anyone from setting it up and using it.

This is a user helping other users with tech questions

forum, you are not addressing apple here  just  fellow users

If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support

this is all you can do