This website contradicts itself. First, it seems to say that cell tower tracking is possible even while the phone is powered off (screenshot #1). But then below that (in the table) it indicates that cell tower triangulation requires the phone to be powered on (screenshot #2). Which is it?

Thank you for the link; that is an informative read.

But where does it indicate that phones continue to ping cell towers while they are powered off?

Do you have an information source to support this claim? (Specifically that cell phones continue to ping cell towers even while powered off.)

iOS and Android have configurable settings which allow the phone to participate in each platform's respective "find my device" network even when the phone is powered off. But these are powered by Bluetooth.

Are you implying that these features also utilize GPS/WiFi when the phone is powered off?

Interesting! I did not know that iOS has this feature. I also did not know that my Pixel phone has this feature. Now I know. Thanks!

How is it tracked if powered off?