Decent lens, but far from perfect...

Thanks for posting. If you've compared different lenses and they show the same thing, then it's not your lenses (you would be spectacularly unlucky to get two bad copies at once, in any event!)

The example you have posted is unfortunately almost the worst possible subject for measuring resolution. There are large areas of solid colour, and some large text. To show resolution close up, you need subjects like fine hairs, fabric with a fine woven pattern or a test chart. At a distance, things like bricks can work as they end up very small in the frame.

Also, if you want to do a comparison of lenses, it will eliminate more variables if you shoot both at - or close to - base iso. That way noise and noise reduction will not interfere with the outcome. That means you can eliminate another variable.

Nonetheless, my first thought on looking at the comparison was the Nikon showed the texture much better. Only there is really no texture on the subject - the apparent texture is noise. On the Fuji image, the noise is smoothed away, leaving it noise free but with terrible acutance.

I would suggest that the main difference between the photographs is not that one is sharper than the other, but that the Nikon image is much noisier than the Fuji image. On the link I sent you, there is a comparison of two brick walls, one with noise and one without. Do you see how much sharper the wall with noise appears? In fact that apparent sharpness is just noise.

Now, we know the Nikon will not show much more noise than the Fuji, as both share the same size of sensor and are at the same iso setting. Something must therefore be different about how the raw images are being developed.

This is why I mentioned about workflow. Unfortunately, there is no way not to have a workflow. Either you use the out of camera JPEGs, and rely on the default manufacturer's workflow, or you have your own workflow for 'cooking' the raw images. Something is wrong with your 'cooking' in the Fuji images!