This script imports an export of Google Photos to Apple Photos. It will recreate albums checks for duplicates before importing. If it finds that a photo is already uploaded, it will asssociate it with the correct album.
This requires python 3.
To use it, make the script executable and then give it the path to the
uncompressed Google Photos takeout folder (usually named Takeout).
The takeout exported from Google must only contain Google Photos data.
You can do this by going to https://takeout.google.com,
deselecting all, then selecting just Google Photos.
If you have a lot of photos it will create multiple zip files. Do not
let Safari autmatically unzip these for you. If you do, it will unzip
each one two a different Takeout folder (e.g. Takeout, Takeout-2, etc).
The zip files must all be uncompressed to the same folder to form a
complete archive.
When running this script on my own photos, I found that after a while the Photos app would start giving an error on import with reporting only "Unknown Error." It appears there is some internal limit on the number of calls to import after which it consistently fails. Restarting the Photos app fixes it. I'm not sure if importing in one big batch would help, you could try importing all the photos first, then just running the script to associate the photos with albums.
The script will create a file called migrate-progress.json in the
directory where you run it. Once it finishes with an album, it will
write folder path to this file. When runnign the script a subsequent
time it will skip any album whose path is in this file. This helps
save time if you need to rerun it due to errors. You can delete the
json if you want to run it from scratch.