Like I said in my previous reply, you will need to use the Get Wheel State BP node and use the axis values that correspond to your joystick’s input to control the vehicle.
The example project should just be plug n play for steering wheels. I haven’t tested the plugin with anything other than the g920, so I’m not sure if there are any extra steps you have to take to get it working. The only thing I can think of to check is to make sure you have the latest version of the Logitech Gaming Software installed and the steering wheel’s firmware is up to date. I also recommend testing the plugin in Standalone, PIE, and Play In Viewport.