Same issue here — 11.0.1. I reinstalled the OS multiple times. I completely wiped the computer and reinstalled from a backup and it still occurs. I even attempted to set it up as new and let it run for a day — but still no iCloud progress.

Sidenote: I have an open question for this on the apple stackexchange It contains some logs I believe are related to the issue. For some reason I am not allowed to link it directly: https://apple.stackexchange.com/q/406920/172012

The issue for me started 2 days after upgrading to Big Sur. Nothing fixed it even a clean install. I also was on the phone with apple support for hours. Downgrading to Catalina worked. After a week of this I updated to Big Sur again yesterday. So far it is ok.

I am still getting the original error message in the latest betas of Xcode and macOS: This bundle is invalid. Apple is not currently accepting applications built with this version of the OS. (ID: 47b6630e-a15f-4ef7-90fc-8fbcc11555a4)

Actually there are a quite a bunch of more specific URLs, although undocumented. You can find a list of the ones discovered so far here. You want to use NSWorkspace.shared.open(URL(string: "x-apple.systempreferences:com.apple.preferences.extensions")!) // or NSWorkspace.shared.open(URL(string: "x-apple.systempreferences:com.apple.preferences.extensions?Share")!) Unfortunately there is no URL publicly known that goes to the page required for finder sync extensions, although Keka has a button to open that page.