Thanks for trying, although understood that you can’t change the resolution when the ViewSonic monitor is connected.
The ViewSonic monitor likely doesn’t work through the DVI port on the dock because the DVI port on the dock is a single link DVI port. This monitor requires a dual link DVI connection to support 1440p.
A workaround for the moment would be to keep this ViewSonic monitor connected to the “HDMI 2K” port, but that does mean that you cannot use the DVI port on the dock.
While I understand this may not be possible, do you have another USB-C computer available in which you could connect to the dock? This would help us understand if this ViewSonic display issue through the HDMI 4K port on the dock occurs external to the computer, but I understand not everyone has a spare USB-C system.
Thanks!
Mitchell