I have the Venus Optics Laowa 15mm f/4.5R Zero-D Shift Lens (Hasselblad X). It is fully manual and very sharp, with great contrast and great colors. I stop down to f/11. I haven't noticed any distortion. Along with the lens, I also bought the Venus Optics Shift Lens Support V3, which I highly recommend, as this is a tripod lens. With a pan-and-tilt head, it's much easier to get things right. The only downside that I've experienced is lens flare from the sun. Without a lens hood, keep the lens in the shade when possible; I use a large hat.
I believe this lens is a bit sharper than the Canon 17mm T/S lens.
Thank you both for your helpful replies. I have been and remain a bit skeptical about buying non Nikon Z lenses; your thoughts are making this a bit easier.