I've been using Canon's mirrorless R system since day one ... Speaking of size, it also has the smallest footprint (give or take a couple of millimeters against the EOS R100) of any EOS R camera.
The Canon EOS R5 Mark II uses a 45 megapixel stacked BSI CMOS image sensor (which Canon told us is different to the R5's similarly specced sensor) paired with the very latest DIGIC X and DIGIC ...