Copy user data to a new user account

iCloud Drive does not work with my primary user account on macOS 14.6.1 on my cMP 4.1>5.1. Files stored in iCloud Drive do not sync – there is nothing at all in the ~/Library/Mobile Documents folder. I have no problems accessing iCloud files on my iPhone or iPad. I have about 30GB of user data in iCloud Drive.

The problems started when I accidentally deleted iCloud files from ~/Library/ while trying to sync from iCloud Drive.

I have signed out of iCloud, rebooted, reset NVRAM, etc. to try to get iCloud Drive to sync, but it hasn’t worked. I have recreated all iCloud folders and files by manually copying them from a Monterey Time Machine backup – to no avail. iPhoto, Calendar, Contacts, etc. all work fine on iCloud – it’s just the iCloud Drive that is broken.

I created a new user account and signed in to iCloud with it. Syncing with iCloud Drive works fine.

I really don’t want to do a full reinstall of macOS Sonoma and then try to copy my user data back using Migration Assistant or Tine Machine Restore, as iCloud Drive is clearly broken on this user account. I also have 2.7TB of user data, so a clean reinstall and restore will take days after iCloud has synced everything (Photos has 500GB of photos and videos alone, plus design, web, and video projects, etc.).

I’m wondering if there is a way to copy all my user data (including ~/Library/ data) to a new user account or if there is a better way to do this. Again, everything works fine except for iCloud Drive.