Problem solved: I updated the dock-related drivers but that made no difference. The dock would still not enumerate on the left USBC port. On a whim I moved it to the back right USBC port, and it registered and the external display came up as expected. After doing so, moving the dock back to the left USBC port worked as it should. Coincidentally I see that I am not the only one with this issue: Issues after BIOS 3.05 update 13th Gen Intel Framework 13
No idea why this worked, but I hope it helps someone else out!