After reading your post again: I understood your post that way that you want to reach the internet through your router. Then you need split-tunneling disabled und NAT for the external clients. But if the clients should reach the internet directly, then split-tunneling has to be enabled.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.