Hi, Duplicated mode is needed when using a KVM, Since We cannot fully control a device when it has two screens in extended mode and we can only remotely control one of them.
Our device can ultimately support 4k@30fps, resolution greater than that will cause a no display problem.
Please try with our mobile APP recently released. Via a browser in mobile device will have some restriction in controlling.
You can download IOS or Android version from the link below.