If you Share your library with your other email you can add all the photos to the library of the second account.Share your library with the second account: https://support.google.com/photos/answer/7378858Accept the share and select Automatically add to library for all photosWait, it is best to leave overnight, until the photos have all been added to the second account before creating any albums.Archived photos are excluded, but works for everything else. Any photos you save from a shared library won’t take up storage, until you stop sharing the library, however this doesn’t appear to work and storage currently remains free, but could change. WARNING only the photos are added to the new account, Albums are not transferred
