Also there is no easy way to export all your photos. I learned this the hard way when I decided to move my photos to iCloud. There used to be an option in Drive to link your Google Photos albums and download them, but they removed it. You can request your data from Google and then download a large ZIP, but I had numerous issues with it and it broke the Live photos from iPhone. In the end I had to manually select ~100-200 photos in the iOS Google Photos app and click Download and then do this for all photos (it will not let you select all at once, there is a limit). And then I enabled iCloud to back up the downloaded photos.