A few of our kitten (Macey) with the 26mm pancake on the Zf at f/2.8, denoised with LR (ISO 11400 and 25600, respectively), RNI Fuji Superia 200 profile-
That's a question for another day For now, pasting what I put in another thread:
Yes, ultimately they are very similar at a glance.
I think the key pros for the Nikon are 1) it renders sharper deeper into the corners, 2) has less vignette, 3) renders a flatter image and 4) has stated weather resistance.
The pros for the TTA are that it has 1) the aperture ring, 2) much better-feeling build quality, 3) more bokeh, and 4) less fringing wide open.
I personally like the wider FOV, build quality, aperture ring, and bokeh qualities more than the Z, so the TTA will be my lens of choice.