Canon R5 II has a
45.0MP Full frame (36 x 24 mm ) sized Stacked CMOS sensor and features Digic X processor. On the other hand, Leica Q2 Monochrom has a
47.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Maestro II processor.
One other difference between these two cameras that is worth mentioning is that Leica Q2 Monochrom's sensor doesn't have an anti-alias (Low-Pass) filter. 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 R5 Mark II and Q2 Monochrom sensor size comparison.
Sensor Size and Resolution Comparison image of Canon R5 II and Leica Q2 Monochrom Cameras
Canon R5 II and Leica Q2 Monochrom 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
Canon R5 II
or the
Leica Q2 Monochrom ,
including hyperfocal distance.