macOS 12.3 will break cloud-storage features used by Dropbox and OneDrive
arstechnica.com
arstechnica.com
This is, of course, Apple's fault for getting their API wrong and then forcing everyone to switch to their broken solution.
You could bring them back by editing source code, but much like the Chromium extension manifest changes, the rest of the code quickly becomes incompatible with the old way of doing things.
I've just checked and it works as expected. Click on "Always Keep on this Device" to keep a local copy of some files.
The only difference is that the OneDrive shortcut in Finder is now under Locations instead of Favourites.
It may be annoying for people needing to re-download all their local content though.
But if they plug into NextCloud/ownCloud, then they got me and about 2 million other homelab users.