iCloud sync and update very, very slow

Any file operations on iCloud controlled directories take many seconds to minutes to complete, e.g., moving, deleting, even changing directories in Finder. I tried to remove Desktop & Documents from my iCloud sync and make a backup, but the message says to let iCloud finish updating first. That was several days ago and I'm only 25% done. I have a very good internet connection (350+ mb/sec), a half empty hard drive, and more than 1TB on iCloud.

This has been happening since I updated to Sonoma 14.4.1. Nothing else has changed in my setup, no new devices, new directories, nothing.

What's going on?

Thank you,

A very frustrated Apple customer.