The reasons I say it is complex is because depending on the sensor technology, resolution, image pipeline, etc. there are many different ways you could compare

The reasons I say it is complex is because depending on the sensor technology, resolution, image pipeline, etc. there are many different ways you could compare image quality. If you compare extremely different sensors, like a 1/3" and full frame, then of course the larger sensor will be better, but comparing say a 1/2" sensor with a 1" sensor is less clear. The smaller pixel sensor will have a better resolution in lp/mm for example, if downscaled to the same resolution as a lower resolution sensor, in many cases you will end up with an image with better detail and less noise (due to averaging out the noise). This is why cameras like the Sony A7iii take a 6K readout and downsample it to 4K for video output. My comment about computational processing still stands though. While a RAW file will give you much more ability to process, complex computational processing just isn't used to nearly the same level in any raw processor I'm aware of (DxO Photolab is probably the most advanced at this, but still is relatively basic), which does make it a valid comparison at the moment. The simple fact is that small sensors these days have closed the gap with larger sensors significantly, while there are areas they are inadequate in, there are other shooting conditions where the differences are minimal which is a statement I would have scoffed at when I started working with cameras 6 years ago.