>>3977202ff 24mp > mft 10mp > ff 45mp
35 > 21 > 19 um/pixel
individual photosite area dictates raw lowlight sensor performance. period.
theimplementation and software magic is another matter and for example panny extracts better noise results from their sensors compared to sony (adjusted for size)
for example the a7s3 isn't 3.5x as good in lowlight compared to gh5s, as photosite area would indicate, only about 2x better judging by youtube side2side comparison videos at iso levels