How to Transfer Google Photos to iCloud and Keep the Dates
How to transfer Google Photos to iCloud: Google's direct transfer, or Takeout plus Apple Photos. What the transfer misses and how to keep the dates.
To transfer Google Photos to iCloud, try Google's own transfer to iCloud Photos first; it is the easiest route, but it often leaves shared albums, some videos and Motion Photos behind. For full control, export with Takeout, write the dates from the .json files into the photos, then import them into Apple Photos.
The direct route is Google's own transfer service, which copies your library to iCloud Photos without you touching a file. It is the easiest option and you should try it first. It does not always move everything, though: shared albums, some videos and Motion Photos are common casualties, and people regularly find a chunk of their library missing on the other side. Count your photos on both ends before you delete anything from Google.
The manual route is Takeout, then import into Apple Photos. This one you control completely, but it walks straight into the date problem. Takeout hands you photos with no capture date inside them and puts the real dates in .json files alongside. Apple Photos does not read those files. It reads EXIF, finds nothing, and files every photo under the day you imported.
Fix the export before you import it, and Apple Photos gets it right the first time. The app writes the true date and GPS into each photo, so your Memories, your Places map and your timeline all work. Do it in the wrong order and you are re-importing forty thousand photos. The first 500 are free to test with.