It was quite an adventure when I exported all my photos from Google Drive. It took Google a couple of days to get everything ready. Afterward, I downloaded around 15 zip files, each with a size of several gigabytes.
It was quite a task to unzip them all, perform deduplication, and import them into iCloud photos.
To keep them synced with S3, I am currently using an app called Photosync.
Just wait until you find out you don't have location data or the dates on photos from about 5 years are wrong. I think there's a reason the drive integration got shuttered.
Now that I think about it though, Takeout might include the location data until... they patch that "bug"to be more in line with the Photos API.
Sorry for this but on the off chance a single person anywhere near Photos sees this, your management chain is full of unrespectable scum. :) Gotta love Google.
It was quite a task to unzip them all, perform deduplication, and import them into iCloud photos.
To keep them synced with S3, I am currently using an app called Photosync.