Google's main business is surveillance advertising, and they pay Apple for the privilege of surveilling their users and returning them advertising. I am sorry but I do not know what else to call it other than surveillance advertising.
Here is a study showing that Apple collects data from Iphone users pretty much the same as Google does from Android phones. https://irishtechnews.ie/trinity-study-privacy-concerns-abou...
Apple has a $5B advertising business of their own. I would be naive to think they do not use any of the data they collect about individuals for their advertising. Their closed source platform and business practices does not enable us to verify what they claim. I have plenty of other resources of information about this, but it is pointless to share if someone does not really want to see it.