Netzpolitik.org actually reported on what you can do with this type of data a while ago. They tricked a databroker into getting a free sample of geolocation data, 3.6 billion datapoints. They were able to build individual movement profiles for people and link that with real identities by putting just a little bit of work in. For a government with access to stuff like palantir this would mean a full movement profile for pretty much everyone with a phone.
German article about movement profiles: https://netzpolitik.org/2024/databroker-files-firma-verschle...
Broader article about their research into the databroker topic:
https://netzpolitik.org/2024/databroker-files-die-grosse-dat...
Wired article for English speakers: https://archive.ph/DmWrw
Wired frames this a little strange, around how the government is powerless to stop it and such, especially considering how they now actively admit this is in their interest.