Both Sony WX500 and Sony TX30 have 18.0 MP resolution sensors but Sony WX500's sensor is 1/2.3 (6.17 x 4.55 mm ) and Sony TX30's sensor is 1/2.3-inch (6.16 x 4.62 mm ).
Since Sony TX30'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 WX500.
Below you can see the WX500 and TX30 sensor size comparison.
Sony WX500 and Sony TX30 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the same focal length and aperture.