Many services and companies argue that metadata is not personal data, but even if that were true by definition of the word, the means to correlate metadata to a real person have existed for how long now?

Just knowing that I receive messages, at certain times, in a certain app, might not be a lot on its own, but as soon as you cross-reference that with other users, it becomes a surveillance goldmine.

And that's what many people seem to miss, I think.
Individually, there might not actually be much, depending on how you use your device. But the word individually gets thrown out the window in our world where everything is interconnected 24/7.

And of course nobody is going to fix these vulnerabilities because the governments want to be able to view that data

Another quote from the article: "The data that is required to 'turn on any push notification service' is quite invasive and can unexpectedly reveal/track your location/store your movement with a third-party marketing company or one of the app stores, which is merely a court order or subpoena away from potentially exposing those personal details."

How is getting a push notification any better at tracking someone than the actual gps and tower data that their phone is CONSTANTLY sending out to their cell providers?

Seems really overblown, like most people hearing this assume it's including contents of the notifications but it doesn't, and if law enforcement wants to put a suspect at a crime scene, they can just get the data from T-Mobile, if it gets to the point they're asking Google or Apple for info, id be much more concerned about all the data and emails stored on the cloud, which they already have no problems giving out.

Am I missing something? What can law enforcement gain from push notification data that they can't get with data from the cell provider already or the wealth of other data collected by Gmail, maps, Uber, etc, which is way more useful than anything a push notification would contain.

Not defending the practice of course, I don't get push notifications because I don't have Google apps installed on my grapheneOS phone, but I'm pretty sure T-Mobile knows my location just as well.