2560x1080 from 2015 macbook air via docking station
 

I have just bought an ultrawide LG monitor with max resolution 2560x1080. I have a 2015 macbook air connected to a wavlink docking station via USB 3.0, and from there I'm connected to the monitor via HDMI. Since my macbook is running OS High Sierra 10.3.6 I downloaded the displaylink driver version 4.3.1 as the website recommends. There is no option to select ultra-wide display resolutions. The sharpest picture is 1960x1080, and there is an option for 2048x1152 which doesn't look so good. Is it even possible to access the ultra-wide resolution with my current setup? Any help appreciated, thanks! Let me know if more info needed.