Downloading iCloud Photos to external hard drive

I have ~50k photos in my iCloud and want to move them to an external hard drive. I do not have enough storage on my Mac to download all of the photos from iCloud to my desktop.

I tried to transfer my Photo library to the hard drive and only about 50% of the photos transferred because the remaining photos are being stored in the cloud and have not downloaded to my laptop. Is there an easy way to make this transfer without losing photos?