If you want every mm from your UWA, don't assign geometric distortion correction.
Maybe vignetting correction is needed. I think this picture looks not badly more distorted without correction.
And use RawTherapee if you want a wider and bigger photo!
According to Dpreview the Max resolution of Z7 is 8256 x 5504. RT made a 8280 x 5512 tiff.
My edit seems to be less saturated and has less contrast than Adobe's and DXO's defaults.
Leica offers multiple resolutions in their recent cameras (M11, Q3). The scaling occurs in firmware, and only certain resolutions are possible (algorithm limitations).
On the other hand, Sigma/Foveon pre-Quattro offers low-res via 2x2 binning on-sensor and the X3F raw image is indeed half the width. A bit less noise and a bit "sharper" at Nyquist.
I call the data accessible by RawDigger "raw" rather than any other data occurring momentarily between the sensor and and the data written to the camera card.
By the way, we should not write "RAW" because that implies a specific raw file-type ".raw" ...
IIRC, Cambridge in Colour used to refer to "Capture Sharpening" as a necessary part of raw conversion in the production of a scene-referred image. RawTherapee now offers Capture Sharpening per se. I call a scene-referred image "pre-processed" hence my distinction. I do realize that most people don't bother with that, instead doing the whole thing from raw to exporting a JPEG in the converter.
As a matter of fact, Sigma's Converter applies a bit of sharpening at the default position of the Sharpness Slider - a subject of mnuch discussion elsewhere.
Capture Sharpening is often applied because raw images (at least as viewed in RawDigger) can be a bit soft, certainly not dripping with MTF at Nyquist ...