2560x1440 on 4K monitor missing

[Kolt]

I've connected my Eizo EV3237 to a Dell D-6000 Docking Station and a Mac running macOS 10.14.3 and DisplayLink version 5.0.1
DisplayLink drivers are installed and working.
But my preferred Resolution is not offered in the Monitor System Prefs Pane: 3008 x 1692 is not offered, not even when I alt-click the scaling settings as described in one of your knowledge base articles.
SwitchResX also does not help.
And I know that the display supports this resolution: When I connect the display directly to the Mac via an USB-C -> MiniDisplayPort Adapter, I can select this resolution and it looks great.
And here are the vendor specs:
https://www.eizoglobal.com/support/c...s_x/index.html

When will you support all the resolutions that the display supports ?
And thanks for you fast answer.