Nikon Z6 III has a
24.0MP Full frame (35.9 x 23.9 mm ) sized Partially-Stacked CMOS sensor and features Expeed 7 processor. On the other hand, Nikon ZR has a
25.0MP Full frame (35.9 x 23.9 mm ) sized Partially-Stacked CMOS sensor and features Expeed 7 processor.
Below you can see the Z6 Mark III and ZR sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon Z6 III and Nikon ZR Cameras
Nikon Z6 III and Nikon ZR have the same sensor sizes so they will provide same level of control over the depth of field when used with 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 Z6 III
or the
Nikon ZR ,
including hyperfocal distance.