Sony RX100 VII has a
20.0MP 1″ (13.2 x 8.8 mm ) sized Stacked BSI-CMOS sensor and features Bionz X processor. On the other hand, Panasonic FP1 has a
12.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor and features Venus Engine IV processor.
Sony RX100 VII's sensor provides 8MP more than Panasonic FP1'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 RX100 VII and FP1 sensor size comparison.
As seen above, Sony RX100 VII has a 4.2x Larger sensor area than Panasonic FP1. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.