Good link.

My interpretation here is that the location of a missing device can be passed around via Bluetooth mesh but that the last send must be sent via cellular or WiFi back to iCloud. So it’s P2P to relay getting location info back to final device with internet connection back to iCloud but the finder still need to connect to iCloud to view updated location.

“Find My works offline by sending out short range Bluetooth signals from the missing device that can be detected by other Apple devices in use nearby. Those nearby devices then relay the detected location of the missing device to iCloud so users can locate it in the Find My app—all while protecting the privacy and security of all the users involved.”