I had similar requirements when last year I completed my switch from Mac OS. In the end I bought a Dell XPS15 9560, I guess an older model with respect to yours.
You should read this thread first (if you haven’t done it already):
https://discuss.pixls.us/t/choosing-a-laptop-with-programming-and-photography-in-mind-reloaded/
In the end I opted for the conventional full-HD screen instead of the 4k. I then bought an external monitor. This makes DT snappier.
The intel graphics is useless for DT so consider that you will always be on the external nvidia card. Perhaps I may switch to Intel when I’m doing other things (internet stuff, and work-related hacking in Python) and am on the move. It’s a bit inconvenient mainly for the noise and increased power usage (using the nvidia card I mean). Things may have improved with later models, I don’t know.
I also had lots of doubts on the real speed of DT and have tried to understand whether it was a problem with the specific version of DT I was using, or my Dell, or something else… you may find interesting to read these other threads I’ve started in this forum, e.g.:
https://discuss.pixls.us/t/darktable-speed-in-general-and-when-using-two-monitors/
https://discuss.pixls.us/t/darktable-performance-in-lighttable-mode-tagging-etc/