According to a reply from UBI-Support to a a user request, ACP is NO LONGER A FEATURE.
Seems like they just removed it from the new UBI-Connect API without caring about the thousands of currently playing people (yes currently over 3k on Steam alone).
I have almost 400 hours in AC:Odyssey and thought i give Origins a try next and actually quite enjoying it. But just removing a sandbox feature like this and let the people click on dead buttons is not the way to do things right.
Very.. very
... lame. To say at least.