I am also trying to get the Khadas Vim working with the NexDock.
I am having trouble getting the Bluetooth to pair with the Vim (can't even list device in bluetoothctl) and the same resolution issue. I tried to force it but managed to green screen the display probably with the wrong refresh rate.
Please let me know if you find any solutions or a Linux distro that works with the NexDock out of the box.
Nice to see other NexDockers out there.