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, Panasonic S5 II X has a
24.0MP Full frame (35.6 x 23.8 mm ) sized CMOS sensor and features Venus Engine processor.
One other difference between these two cameras that is worth mentioning is that Panasonic S5 II X'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 S5 Mark II X sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon Z5 II and Panasonic S5 II X Cameras
Nikon Z5 II and Panasonic S5 II X 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
Panasonic S5 II X ,
including hyperfocal distance.