Thanks Alfred, but that's not useful at all. I'm well aware of how iCD works, and that if you delete from it, it deletes everywhere. But you're not listening to what I'm trying to achieve. For whatever reason, I'm essentially trying to store my local Documents folder in the cloud. Ideally using iCD because I've paid for a ton of storage on it, and have used hardly any of it.
With regards to not thinking of iCD as a type of backup: it is a type of backup, because if i lose my MacBook, all of my current files would still be accessible on all my other devices. And even better, when I get a new MacBook, I just connect it back up to iCloud, and all my files will get synced back down... i.e. restored.
And before you tell me this is not a good backup strategy, for the record I have a TimeCapsule too. But storing things in the cloud not only creates redundancy from my TimeCapsule, but is also very convenient.
Now could someone please just tell me how to symlink to the iCloud Drive, and make it work? Would my idea of doing it in reverse work?