I'm using an M1 MacBook with the
Targus dock and an
active HDMI to DisplayPort converter. Then the DisplayPort is connected to the LG Ultrafine via the Moshi DisplayPort to USB-C adapter sold by Apple.
In this configuration, I'm able to get resolutions from 3840x2160 to 1280x720, including 2560x1440.
I've got dual LG Ultrafine 4ks—one is on the native thunderbolt port and the second is on the hack (dock HDMI port -> DisplayPort adapter -> DisplayPort to USB-C cable).
However... I've yet to figure out how to adjust brightness on my LG Ultrafine. Any idea how you do that?