Looking at the reason why you want to do that, the Application Server offers a Web UI that you can access from your browser. It’s not a program with a GUI that you can only view on the local server.
So what you could do is install Application and Network Server both on the Ubuntu Server Machine, open the Web UI Port (Usually 8080 I think) and anyone who can access your Server can also open the Application Server UI in the Browser. (I assume that you have some local installation where no SSL e.g. is needed, otherwise you’d have to bridge the Port via NGinx e.g.)
Setting up the Application Server and Network Server in different locations also works if the 2 machines can reach each other (e.g. not in 2 different natted private networks). Let’s assume you want to set up the Networkserver on Machine A and the Appilcation Server on Machine B. You still need Postgres and Redis on both servers but you can install those locally (At least that’s how I understand it, correct me if I’m wrong). Then in the Application Server UI you’ll have to add the Network Server. When adding the network server, you have to enter the Address of the Network Server. This is e.g. localhost:8000 if you have it on your local machine but could also be e.g. 192.168.0.33:8000 if you have it running on a machine with that IP. The Port you have to open then is only that one that the Network server exposes (Again correct me if I’m wrong, that’s how I understand it but I haven’t tested it yet).
With MQTT it depends a bit on your setup, e.g. I anyway have a 3rd server running the MQTT, I’m not sure whether MQTT would work if you set it up locally on both servers.