Our iCloud Drive appears in our DOpus 10 folder tree only in C:\Users\Name\iCloud Drive. Is there a way to have it appear as a separate device in the main folder tree as Dropbox and OneDrive do?
If iCloud registers itself in the same way that Dropbox and OneDrive do then it should also appear in the folder tree, since Opus 10 didn't do anything special or specific for Dropbox and OneDrive; it just adds things to the tree that put themselves in the appropriate place in the registry.
But if iCloud isn't doing that then there isn't a setting to make an arbitrary folder appear at the top-level of the tree.
If the aim is to get quick access to the folder, you could create a toolbar button or hotkey which jumps directly to it. If you need help setting that up, let me know and I'll provide instructions.