[Brightcolours]

Dave, it "overheats" when doing stuff no other comparable camera can do: Downsampled from 8K60 4K60, saving internally.
Canon told us so, and also the reason: They wanted to keep the camera compact and retain the level of weather sealing (so they did not consider a fan). The A7 III heats up quicker/more, the R5 appears to have rather conservative overheating protection. The A7 III cools down quicker, due to the new heat sink structure Sony introduced in this model.

Now gain to the simple facts: 4K60 is NOT a normal shooting setting. 4K24/25/30 are, and they do not "overheat". Another fact: the A7 III does overheat doing the same thing sooner in for instance the french summer.
So you have a mode you would hardly ever use, and not in long duration takes, and according to you are pissed off that Canon has not been upfront? In what have they not "been upfront" exactly?

Back to the facts: The R5 offers a lot more than the A7 III: much IBIS, way less jello, better 4K, 8K, 45mp. The A7III does better high ISO (albeit with much lower resolution for stills) and has better single battery battery time. It has a bigger native lens lineup, and costs a few 100 $ less.

For whatever reason you are bent on pushing the "overheating is a shame" narrative, no matter what.

   You keep repeating the same or similar specs ..... I've seen them so many times I really don't need to see them again .....

You just need to see that the R5 overheats and Canon is dishonest over and over again, right?