All I can say is that if I wanted to centrally manage several Duplicati installs, I would do a basic install of Duplicati on each computer and use something like the Python command line client to manage them.
possibly adding a VPN to secure the config link.
I’d be way too wary of coupling a beta software with a network local protocol that is a bad fit for remote links and using a software like Samba notoriously very difficult to setup correctly (and stay setup right with possible updates both in Windows and Samba) to even think of what you are wanting to do.
You can use Settings to allow remote web based access to Duplicati from your systems on the network.
Command line client will need this anyway, if you go that route, but you could also browse there directly.
You can also just set the Duplicati Schedule tab to do automatic backup. No need to remotely run them.