See my Leica M wishlist.
This page looks at the performance of the Zeiss ZM 35mm f/1.4 Distagon on the Nikon Z7 from f/1.4 through f/11, sharpness and field curvature in particular. This scene is particularly instructive in showing the excellent sharpness of the Zeiss ZM 35mm f/1.4 Distagon wide open at f/1.4, but in a strongly curved field greatly exaggerated by the too-thick sensor cover glass.
In Guide to Leica*:
Includes images up to full camera resolution from f/1.4 through f/11.
The Zeiss ZM 35/1.4 Distagon delivers sharpness edge to edge on the 24-megapixel Leica M240 with its 0.8mm sensor cover glass. However, when adapting it to mirrorless cameras like the Nikon Z7, optical performance can be degraded considerably as shown in MTF on Mirrorless Cameras. The Nikon Z7 offers somewhat thinner sensor cover glass than Sony mirrorless, so the Zeiss ZM 35/1.4 might be expected to be somewhat less degraded, but the sensor cover glass still exerts a strong influence.