I don’t have another controller unfortunately. The Horipad controller is designed for the Switch but it does work on PC too (at least in Godot it does, I haven’t tested it in Unity)
The controller should work imp. However I'm using unitys new input system for input and it could be an issue with how it interprets that specific controller. Or it might be an issue with the UI. That your're actually joining but the UI doesn't respond.