Macbook pro extended desktop cut off by external monitor

I'm using a 2016 Macbook Pro TB with a 32 inch Benq PD3200U via a Caldigit T3 dock. The issue I'm trying to get rid of is that the monitor is cutting off part of the screen (i.e. the desktop is larger than the monitor). The Apple logo in the upper left hand corner of the desktop spills back onto the Macbook monitor, and there's a section of the external monitor desktop that shows up on the macbook monitor.

Hopefully that describes it well enough, but it seems like the desktop size is too big for the monitor setup, and there fore extended desktop mode is behaving strangely.

I've tried scaling it in systems settings, I've tried option click to try all the different resolutions, I've tried changing cables, I've tried changing arrangements. This is driving me nuts, thanks!