I concur with Tagbert. Don't delete iCloud drive. At least until you make sure ALL your photos are on your external drive as jpeg or other photo types. Deleting photos from the iCloud drive (assuming you are using the Mac's Photos app to view the photos on iCloud or on iCloud.com) will delete the photos from all devices unless you have Exported them. (Of course, they will still be in Recently Deleted until you delete them there also.)
If your 'Albums' are in Mac's Photos app, you may already know that photos in Albums are just links to the photos in the Photos Library. To keep the Albums as folders, you have to Export each Album to a folder of the same name. If you also export everything from All Photos, the photos that were in albums will be duplicated.
I would like to know more details about your current setup and what you want to accomplish. What apps are you using to manage your photos? How are the photos organized on your drives? How were the old photos incorporated into your Photo Library? What methods are you using to put the photos and videos on the external drive? What is your plan for managing your photos going forward.