DVI to HDMI cables tend to work reliably since DVI and HDMI are electrically identical up to 1920x1200 resolution, but I remember reading posts saying that HDMI to DVI cables didn't work with the XPS 15 9570's HDMI output, so I guess that's a possibility.
However, if you've just recently purchased the D3100, you may really want to rethink that choice in dock model. First, that dock doesn't charge the system, and there are other docks that plug into the 5490's USB-C port that can facilitate that. And second, DisplayLink really isn't an ideal choice when you have the option to use a dock that taps into the native GPU output available on the USB-C port. Take a look at the post I wrote in this thread (the post marked as the answer) for my write-up of DisplayLink. The D6000 dock I mentioned there would at least be able to charge that system, but it too uses DisplayLink. The Latitude 5490 doesn't have Thunderbolt 3, so you couldn't use the TB16 dock, but you could use the WD15. That would charge your system and use native GPU outputs. So unless you actually need more than dual 1080p external displays (or you need to use that dock with other systems that don't have USB-C), you might want to consider returning the D3100 in favor of a WD15.