Canon R10 has a 24.0MP APS-C (22.2 x 14.8 mm ) sized CMOS sensor and features Digic X processor. On the other hand, Canon M6 MII has a 33.0MP APS-C (22.3 x 14.9 mm ) sized CMOS sensor and features DIGIC 8 processor.
Canon M6 MII's sensor provides 9MP more than Canon R10'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.
Below you can see the R10 and M6 II sensor size comparison.
Canon R10 and Canon M6 MII have almost the same sensor size so none of them has any significant advantage over other in providing control over depth of field when used with same focal length and aperture.