Why Does Google Takeout Split My Export Into Parts?
Google caps each archive, so big libraries arrive in numbered zips. Here is the mistake to avoid.
Because Google caps the size of each archive. Pick 2 GB and a 200 GB library arrives as a hundred files. Pick 50 GB and it arrives as four, but a failed download costs you an hour.
The important part is what this does to your files. A photo can land in one part while its .json file lands in another. They are only reunited when everything is unpacked into the same folder.
That is the mistake people make: unzipping each part into its own folder. Do that and a lot of photos appear to have no metadata, when really it is sitting in the folder next door.
Unzip everything into one folder, then run the app across the whole thing at once. It treats the parts as a single library, finds the pairs wherever they landed, and tells you if a part looks missing before it starts. The first 500 photos are free.