Ricoh GR IIIx has a
24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor . On the other hand, Nikon D500 has a
21.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features Expeed 5 processor.
Another similarity between these two cameras is that both Nikon D500 and Ricoh GR IIIx sensors lack anti-alias (Low-Pass) filters. 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 GR IIIx and D500 sensor size comparison.
Sensor Size and Resolution Comparison image of Ricoh GR IIIx and Nikon D500 Cameras
Ricoh GR IIIx and Nikon D500 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
Ricoh GR IIIx
or the
Nikon D500 ,
including hyperfocal distance.