[gspr]

I have a very similar Dell. I'm not sure it fits your use case, but I just run on the Intel graphics with the nvidia one powered down and no nvidia drivers installed. The Intel card runs multi-monitor 4K desktop stuff smooth as silk (I use Wayland, but I checked X too).

Whenever I need to run CUDA stuff (my only use case for the nvidia GPU), I power it up, and pass it through to a VM that also runs Linux, but with the horrid nvidia stuff installed. Works like a charm.

[ohgodplsno]

I'd be curious to see your setup, purely because I have never found a way to have the iGPU handle the HDMI output. It seems it's directly soldered to the Nvidia card.

[gspr]

Strange. I thought that solution (output soldered onto the GeForce) was discontinued a long time ago for this range of machines. My setup works really well both with the HDMI output, with the Thunderbolt output, and of course with the laptop display.

I have this going on two very similar machines: A circa 2017 XPS 9560, and a circa 2020 XPS 7590. Both are 15". I don't have the 9560 near me at the moment, but the 7590 has

00:02.0 VGA compatible controller: Intel Corporation CoffeeLake-H GT2 [UHD Graphics 630]

01:00.0 3D controller: NVIDIA Corporation TU117M [GeForce GTX 1650 Mobile / Max-Q] (rev ff)

I'm happy to help you debug if you want. What happens if you remove all nvidia drivers and plug something into the HDMI port? Do you notice any response from the external screen if you hit for example control f2?