Up until now, most of the overheating hyperbole has been hypothetical. It’s based on documentation that Canon has released. But how closely does it represent the real world? Well, the fact that Canon has apparently patented an active cooling EF to RF adapter should be a big clue. But if you needed some real-world evidence, check this out.
Johnnie Behiri over at Cinema5D recently used the Canon EOS R6 for a couple of days shooting in Japan to produce a short film as part of his review of the camera. It was a pre-production unit, and perhaps there have been some changes to the final production camera, but this assessment does not look good at all.