The “closed source ecosystem” is not nearly as restrictive as people make it out to be and is something that you willingly sign up for when buying apple products.

Not sure where you got the idea of “icloud syncing your every move” but literally every icloud implementation can be disabled at your discretion.

I for one only have my reminders, wallet, calendar and drive synced.

Even with that said, none of this implies a lack of privacy in any way.

"the researchers' iPhone transmitted more kinds of data, including device location, the device's local Internet Protocol (IP) address and the Wi-Fi network identifiers — the MAC addresses — of other devices on the local network, including home Wi-Fi routers."