MacBook Pro 15" 2018 cannot display proper resolution on QHD display

I've purchased a BenQ PD2705Q monitor (QHD 2560x1440 resolution) for use with my 2018 15" MacBook Pro. (radeon Pro 560X 4GB) The native display is a Retina 2880x1800.

I'm connecting through USB-C. The monitor will only show 1080p resolution no matter what I do. This results in quite a soft image. I thought this monitor would be a great choice blending sharpness, price, and color calibration for my photo/ video editing.

Was it too much to assume the mac can run the native display AND 2560x1440 at the same time? An upscaled 27" 1080p monitor is just not doing it for me, and I don't have the $700 for the lg 4k monitor. Plus they are hard to find.

When opening display tab on about this Mac, it's showing the external monitor as a 30.5 inch 1080p monitor. It's a 27" 1440p monitor. I've tried HDMI, same problem. the Mac just seems to refuse to display 2560x1440 in any configuration I've tried.