Not so easy...VisionOS like iOS does not intrinsically show other networked devices under Locations as MacOS does. So one will have to figure out what network address to use in the VisionOS Files Connect to Server dialog. Will report back if I figure out how to do this using the Mac's ip address. I actually expect Dropbox and Apple will sort this out pretty soon.As a temporary measure, could one run DropBox on a Mac, then connect to the Mac as a file provider with Vision Pro, then use Files on AVP to access the Mac's DropBox folder?
In short, use a Mac as a mediator between AVP and DropBox.