Below you can see the front-view size comparison of the Pentax K-1 II and Pentax K-S2. The Pentax K-S2 is clearly the smaller of the two cameras. Its body is 14 mm narrower, 19 mm shorter and 13 mm thinner than the Pentax K-1 II.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.