Samsung NX11 has a
15.0MP APS-C (23.4 x 15.6 mm ) sized CMOS sensor and features DRIM Engine processor. On the other hand, Canon SL3 has a
24.0MP APS-C (22.3 x 14.9 mm ) sized CMOS sensor and features DIGIC 8 processor.
Canon SL3's sensor provides 9MP more than Samsung NX11'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 NX11 and SL3 sensor size comparison.
Samsung NX11 and Canon SL3 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.