Are you trying to tell me that the host server is showing the ad, because last I checked, with my whitelist firewall, I never see ads because all ads are links to the ad server you are actually visiting. It is no different than opening up the webpage and connection to them. They get all the same fingerprinting info.
I’m not saying one way or another here, but there is no such thing as anonymous data collection. It only takes 2-3 unique identifiers to connect a person between a known and anonymous data set and there are almost always quite a few more unique identifiers than this in any given dataset. When I hear anyone say stalkerware is anonymous, I assume they are no longer just a privateer of a foreign drug cartel level state, instead they are full blown slave trader pirates fit for the gallows or worse.