iCloud download took forever

It has been extremely slow to read or retrieve files from the icloud Desktop and Downloads folders, so I’ve been trying for weeks to download my resources to the local machine. However, this now seems nearly impossible. I’ve been able to download individual files, but not entire folders. For example, a single 1GB folder located on my Desktop—which has been moved to iCloud—could not be transferred overnight. Ironically, uploading everything from my Mac to iCloud only took one night, but downloading even just 1% back seems unachievable no matter how long I wait.

Yesterday, I spent over 6 hours on the phone with both an "Advisor" and a "Senior Advisor" from Apple’s call center. I followed the instructions given to me over the phone, but at one point the call was disconnected. I then received two emails stating that the advisor could not reach me, even though other advisors had been able to. After that, the messaging feature tied to my case expired shortly after I sent a message. I had to re-explain the entire situation to new advisors, which wasted even more time. They told me my case already had an assigned representative, and if I wanted to switch advisors, I would need to open a new case—further delaying any resolution.

I’m requesting a technical walkthrough from someone who truly understands what’s happening—someone who can explain the issue in technical terms. During the attempt to transfer my files from iCloud back to local storage, I lost several important files. Some files were corrupted (only metadata remains), and the originals were deleted from iCloud. This has made me feel deeply insecure about storing my information on iCloud.

I urgently need help with the file transfer process back to local storage, especially since I’ve had days where I couldn’t even open files saved on iCloud via my MacBook. I would be grateful for guidance from anyone in this community who has tips or insights on how to solve this issue.

I can no longer go through the call center again and spend another day speaking with someone who lacks the technical expertise to address the problem and left in the middle of a conversation.