Did you ever get this working? I have a simular problem and the
workaround I found is to use the "nvidia-driver-96xx" port instead of
the regular "nvidia-driver" port. I can not remember the exact model
of the Dell FP display that I have ( it is at work) but it is the same
No, I never got it working with the latest version of the driver. I
downgraded the port to 100.14.11 instead of using the 96xx stuff, but
the issue with the latest driver remains.