Why Are My People and Face Tags Missing From Google Takeout?
Named people appear in the .json sidecars, but face grouping itself does not export. Here is what you actually get back.
You get the names, but not the face recognition.
Where you named someone in Google Photos, the sidecar for photos they appear in has a people list with that name in it. That is real and useful. What does not export is the underlying face model: the grouping, the thumbnails, the ability to click a face and see every photo of that person. That is Google's own processing, it never leaves Google, and no export format could carry it.
So when you move to another app, you start face grouping again from scratch. Immich, PhotoPrism and digiKam all do their own face detection and will rebuild it over time from your library. Some of them can read names from XMP tags if the names are written into the files.
The names, dates, locations and captions are the parts worth rescuing, because they are the parts that were written down. The app pulls them out of the sidecars and writes the standard ones into your photos, so your new library starts with real metadata rather than an empty timeline. Everything runs on your own computer, and the first 500 photos are free.