Canon 7D has a
18.0MP APS-C (22.3 x 14.9 mm ) sized CMOS sensor and features Dual Digic 4 processor. On the other hand, Canon R10 has a
24.0MP APS-C (22.2 x 14.8 mm ) sized CMOS sensor and features Digic X processor.
Canon R10's sensor provides 6MP more than Canon 7D'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 7D and R10 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 7D and Canon R10 Cameras
Canon 7D and Canon R10 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.