Below you can see the front-view size comparison of the Fujifilm X-A3 and Panasonic GX85. The Fujifilm X-A3 is clearly the smaller of the two cameras. Its body is 5mm narrower, 4 mm shorter and 4 mm thinner than the Panasonic GX85.
The chart below depicts how two cameras compare with average dimensions of the cameras in their class.