Both Sony A7R and Pentax K-1 II have 36.0 MP resolution sensors but Sony A7R's sensor is Full frame (35.9 x 24 mm ) and Pentax K-1 II's sensor is Full frame (35.9 x 24 mm ).
Since Pentax K-1 II's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Sony A7R.
Another similarity between these two cameras is that both Pentax K-1 II and Sony A7R sensors lack anti-alias (Low-Pass) filters. 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 A7R and K-1 Mark II sensor size comparison.
Sony A7R and Pentax K-1 II 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.