>>4204299There really isn't much difference until the highest ISOs. If "high ISO" for you means 3200 or 12,800 then you might as well shoot the high resolution sensor. The resolution gap shrinks as ISO climbs but you still capture more detail, and comparable noise at the same view size.
But if you need to do something extreme and will be shooting 51k or 102k ISO then the lower resolution sensors pull ahead.
Note that while the A7s bodies have a reputation for having the cleanest high ISO sensors, a number of 20-24mp bodies now roughly match them or even edge them out. The Canon R6, for example, is a bit cleaner at 102k than the A7s III.
