Hey guys, another me too but a few twists.
I've been having this problem for several weeks but in my case I'm on macOS 12.6.7 because I am on two 2015 MacBook pros.
I had one Mac on 12.2 when I noticed this issue (due to Dropbox and macOS file provider issues which I won't get into). And the other Mac was on 12.6.6. First I saw safari bookmarks were not syncing on both Macs and icloud drive files were not syncing.
If a file was created on iCloud.com they would sync to both my iPhones on iOS 16 and sometimes to the Macs. But any file created on either Mac would not sync upstream. Sometimes I could make it go with kill all bird and the other suggestions made here (sign out of iCloud, delete al files, etc) but they were short term fix only, so not really fixed.
So I went nuclear and reformatted both Macs and installed 12.6.6 with no 3rd party apps whatsoever. At first it seemed normal again but problems quickly came back.
Tried all the cloud sign out tricks again to no avail. Tried different dns, different ISP. Nothing works.
iCal, Photos, Contacts, Mail and notes seem okay, but iCloud Drive and Safari Bookmarks only work correctly on iClooud.com iOS but not on macOS 12.6x
So, it seems it's not Ventura - maybe it's iCloud for macOS in general. File provider issue maybe?