Android's GLS service has an absolute insane data ingestion pipeline consisting of sensor fusion from GPS, Wifi, accelerometer, barometric data, and cell tower locations. It's accurate to within meters, can locate you inside buildings, can count your footsteps, and even knows what floor you've been on.
It's been used by Google to tune its indoor WiFi maps and improve location accuracy for years.
Anyone who has high location accuracy mode turned on and has Google Play Services has already been unwittingly uploading "anonymized" location data multiple times an hour for literally years. In many cases such anonymized data is accurate to within a meter and contains accelerometer data that can literally count your footsteps and determine if you are walking, running, riding in a car, etc. Anonymized GLS data is what informs traffic congestion and many other "non scary" services.
Google believes the negotiation of a 7-day expiration of randomized UID is sufficient anonymization to meet the legal definition in all of its markets. It might be right about the legal definition. It's wrong if it believes it actually anonymizes data. Google believes a popup notifying that high accuracy mode may upload "anonymized usage data" to Google's services constitutes informed consent according to GDPR. I think the EU would disagree if they knew the technical capabilities of Google's infrastructure.
Google's internal privacy review system believes that they are safeguarding the privacy of its users. Their model does not take into account NSLs or interference from intelligence agencies. And it absolutely did not foresee this.
The surveillance dystopia is here, folks, and your Android phone won't do anything noticeably different. They'll flip some switches in their ingestion pipeline and have an insanely powerful draconian surveillance network instantly.
It's over.