Test photos aren't really intended to be interesting.. just personal testing of focus modes, exposure adjustments, in-camera jpeg processing, etc.. I literally walk around and shoot anything that catches my eye, sometimes they are interesting, most times not.

Noise is really smooth, and not really noticeable until really high ISO settings. Most of the time down sampling the image makes it film like (good film) and barely noticeable.
If clean up is needed there is still a lot of detail retained. The smoothness of the noise retains smoothness in out of focus areas keeping the bokeh nice.
Happy with colors and saturation. Auto white balance is practically flawless.

On some of the images in this Z5 Gallery I was using my old (film days) Canon 24-85 f/3.5-4.5 USM which is bleeding sharp on my Canon bodies - but not so much on the Z5.
This is likely due to adapted focus translation - but getting my Nikon 24-85G back from Nikon repair in a few weeks, so not worried about adapted performance of that specific lens.
On that note, better Canon lenses (newer) work really well on my Viltrox adapter and are easily useable for just about everything.