Isn't it a little disingenuous to call analytics tools "adtech". Yes, you can integrate analytics with adtech platforms, by even in isolation, knowing how your users use your own site and how they arrived there, allows you to better serve them.
In a physical place of business, for example, a retail store or restaurant, keeping track of what times or parts of the store were busiest, or where people spent the most time, would allow you to eliminate waste from your business, and sometimes that involves knowing how many unique customer foot traffic you're getting.
Is it possible to use google analytics without the resulting data being accessible by google ads or search teams? I would assume that they don't let you opt out of org-internal data sharing.
There are also ways to configure Google Analytics to fuzz IP addresses, essentially de-anonymizing them, as well as setting up explicit data retention periods.
EDIT (responding to grandparent comment): Even so, I'm not sure it's disingenuous to call products adtech which are provided by a company whose main business is advertising, and which are often configured to contribute to the advertising business, even if it's possible to use them for purposes other than advertising. At that point, maybe it's just adtech that's being repurposed.
In a physical place of business, for example, a retail store or restaurant, keeping track of what times or parts of the store were busiest, or where people spent the most time, would allow you to eliminate waste from your business, and sometimes that involves knowing how many unique customer foot traffic you're getting.