It appears you are facing two distinct iCloud issues: a 1,000-item selection limit for web downloads and incomplete zip files where the number of items downloaded is less than what was selected. The selection limit is an intentional restriction on the iCloud.com interface. The discrepancy in your download count, such as seeing 54 items selected but only 46 items downloaded, is often caused by unsupported file formats, incomplete uploads from the original device, or issues with HEIC/HEVC processing during the zip creation.
There are several reasons why your downloads might be incomplete. When downloading multiple videos, iCloud's server-side "zipping" process can fail to include certain files if it encounters a sync error or a file format it cannot properly package at that moment. Additionally, if "Optimize Storage" was active when a video was originally uploaded, the full-resolution file might not have fully synced to the cloud, leaving only a placeholder that cannot be downloaded. Some items may also be counted twice in the interface, such as an edited version and its original, but they are only packaged once in the final download folder.
To bypass the 1,000-item limit and ensure no files are missed, you should use more robust archival methods. The most comprehensive option is an Apple Privacy Request through privacy.apple.com. Apple will bundle your entire library into downloadable zip files of up to 25GB each without you needing to select items manually. If you have access to a Mac, you can open Photos > Settings > iCloud and select "Download Originals to this Mac" to sync your entire library locally.
PC users can use iCloud for Windows to sync their library directly to File Explorer. For advanced users, third-party tools like icloud-photos-downloader on GitHub can automate the process and bypass web-based limitations. These methods are generally more reliable than the web interface for large-scale archiving.
