Third party SDKs also report your location to these services[0], which makes it trivial to track your phone to your location (or they could just buy that info directly from the carrier).

Your home ISP's assigned IP is also in a database with your name and a unique identifier. So it doesn't matter what adblocking you use, they still know where the hits are coming from.

All this data is traded around the ad "ecosystem" and integrated real-time, so it can be milliseconds from action to ad-impression.

[0] https://www.nytimes.com/interactive/2019/12/19/opinion/locat...