S3422DWG, native 3440x1440 not working with HDMI 1.4

My Dell S3422DWG 34" ultrawide gaming monitor is not working at its native resolution of 3440x1440 when connected to my HP EliteBook 840 G5 via an HDMI 1.4b port and the cable provided with the monitor. I have updated firmware and drivers of the monitor as well as the graphics drivers for the Intel UHD 620 integrated graphics. My understanding is that HDMI 1.4b can support 4k @ 30Hz and since 3440x1440 is a lower resolution than full 4k, it should be able to support this monitor's native resolution at least at 30Hz as well, correct? The only issue I can think of is that maybe this monitor cannot throttle all the way down to 30Hz since it's max resolution through HDMI is 100Hz? When I look in the advanced display settings, the lowest refresh rate in the drop down menu for the monitor is 50Hz. Can anyone shed some light on this? Maybe it is a software issue and not a hardware issue? Dell tech support was, unsurprisingly, a waste of time. As a side note, the monitor works great without changing any settings when connected to my newer laptop via HDMI 2.0 but that might be because of the Intel Iris Xe graphics or something else...

Thanks in advance.