Panasonic S1H has a
24.0MP Full frame (35.6 x 23.8 mm ) sized CMOS sensor and features Venus Engine processor. On the other hand, Sony ZV-E1 has a
12.0MP Full frame (35.6 x 23.8 mm ) sized BSI-CMOS sensor and features Bionz XR processor.
Panasonic S1H's sensor provides 12MP more than Sony ZV-E1's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the S1H and ZV-E1 sensor size comparison.
Panasonic S1H and Sony ZV-E1 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. On the other hand, since Sony ZV-E1 has 99% larger pixel area (70.55µm2 vs 35.30µm2) compared to Panasonic S1H, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.