There's a HUGE important aspect that you're missing: The IP Address is NOT the only thing that makes this data into personal data.
Google Analytics generates a visitor ID by rolling a random number and storing it in a first-party cookie. This is how GA tells that two visits a week apart came from the same user. This value has been ruled to constitute Personal Data. This is a very big deal, and only a little bit surprising.
Google Analytics generates a visitor ID by rolling a random number and storing it in a first-party cookie. This is how GA tells that two visits a week apart came from the same user. This value has been ruled to constitute Personal Data. This is a very big deal, and only a little bit surprising.