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.
No, the Nikon Z6s is already rumoured to have the same sensor with a new processor to have 4k60p video, A7III used a similar sensor so the A7IV is expected to be the same as well, and it will cost more than 2000$, so it will match the EOS R6.
Going to 30MP will not make sense from a video perspective in a budget model.
Each test is done in different conditions that's why I don't link them, I did my own with the EOS R and I know what ISO I am fine with. That's what everyone should do, these graphs are worth a look, maybe better than DXO, but they are really not something to 'follow by heart'.
Take a look at this for instance. The old 36MP Sony sensor in a Pentax DSLR body looks to have
better usable dynamic range than the brand spanking new 61MP A7RIV. Does that show anywhere in the graphs? No, absolutely not.
Yes that's why I don't expect the R1 to be a 1DX III mirrorless, it's going to evolve more.
By the way, we don't know the full specs, if it is a different sensor, than it might not do FF 4k 60p, it might do it cropped.