Just in case you were looking for a way to edit the WebUI address without opening the WebUI (because you can’t, because you only have ssh access to the server and the default address is localhost):
The config file in ~/.local/share/qBittorrent/qBittorrent.conf takes
[Preferences]
WebUI/Address=[address]
You could also use ssh forwarding for the web UI port, e.g. ssh -L 8080:192.168.0.1:80 user@myvps.com