1) I don't think this competes with the A7III, a camera that was released 2.5 years ago. The A7IV will have close to 30mp, if not higher. They're too different to be competing. The R6 shoots faster than the A7III, too, including in e-shutter mode. I think the A7IV will compete with the R Mk. II, if we get one, but honestly, I don't see Canon competing directly against the A7IV. Maybe the R5 does? We'll see what Sony announces.
2) People bring that point up time and again, and yet no one can produce images that demonstrate more difference than the results of the test charts. If there are test images that show a major noise difference, I'd like to see them, but I've never seen them posted around here.
3) I'm playing devil's advocate. My point is how insane the specs are, and how close they are to the 1DX-line, at 1/3 to 1/2 the cost.