Q: You have 0 photos and 0 videos stored in iCloud. Your photos and videos are using 2.1 GB!

Sorry, I think the clue is right in your screenshot.

The storage they are referring is on your device, not the cloud. It looks like you have never enabled the iCloud library to upload your local photos to the cloud.

Go to Settings > General > Storage and iCloud Usage > Manage Storage (from the upper section) and see how much space your photos are taking up.

Hello there,
currently, there is a massive problem with the Apple iCloud, I have since the beginning of December the same problem.
greetings

I am currently facing a same problem with you.

I am having the same problem. My iCloud storage was full, I disabled iCloud photo library in all devices and erased all photos to free some storage but it seems Ilike  have 2,3GB of stuff that I can't erase.

Does anybody found a solution to this?

Did you delete the photos at iCloud.com? Even after deleting them, they will remain for 30 days unless you delete them from the Recently Deleted album.