You may think you're protecting a computer with a VPN, Location turned off and various privacy strategies, but without awareness of all your devices, Google and other Big tech could be spying on all your devices at once, validating information among them like IP addresses and locations.
Google is also running perpetual little programs that do telemetry for Google even while devices are not in use. Information mismatches between devices (because of VPN use for example) can be auto-corrected based on matching devices with historical records that cannot be erased.
There are many many tricks and we are not aware of them, you will think you have privacy but in reality you won't. You need to understand what's involved and your knowledge needs to be brought up a notch.
Source: Rob Braxman Tech