Nikon Z5 II has a
25.0MP Full frame (35.9 x 23.9 mm ) sized BSI-CMOS sensor and features Expeed 7 processor. On the other hand, Sony A7C II has a
33.0MP Full frame (35.8 x 23.8 mm ) sized BSI-CMOS sensor and features Bionz XR processor.
Sony A7C II's sensor provides 8MP more than Nikon Z5 II's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
One other difference between these two cameras that is worth mentioning is that Sony A7C II's sensor doesn't have an anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the Z5 II and A7C II sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon Z5 II and Sony A7C II Cameras
Nikon Z5 II and Sony A7C II have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Nikon Z5 II
or the
Sony A7C II ,
including hyperfocal distance.