Latitude 5540 UWHD issue

Hi,

I've got a 29" LG ultrawide monitor and would like to use it with my 5540 laptop (I7-1365U with IrisXE), but it only recognize a 1920x1080 resolution. I use a USB-C dock, which is connected to my monitor through HDMI.

Tried direct HDMI to HDMI connection with laptop port, didn't work too.

I've tried updating the drivers, installing intel drivers and etc... But nothing worked. It keeps telling me my screen is on 1920*1080, whereas it works perfectly with 2560x1080 resolution on my desktop (display port).

Thanks in advance for your help