Request for Assistance with Missing iCloud Photos

I need your assistance regarding my iCloud Photos.

Two months ago, I deleted many photos from my iPhone in order to free up storage space. However, I had previously purchased additional iCloud storage, and I am confident that all my photos and videos (more than 20,000 items) had been backed up to iCloud.

Currently, when I log in to iCloud, I can only see around 844 photos and 60 videos. The “Recently Deleted” folder is empty. At the same time, when I use the Windows Photos application with iCloud integration, I can still see the full photo library listed (more than 37,000 photos and over 2,000 videos), but the files do not open or download.

Could you please help me understand how I can recover all of my old photos and videos that were previously backed up to iCloud?

Thank you for your support.