I never even suspected that the solution might be this simple. I don’t have an EOS R5, but I figured if it was this easy to get around Canon’s time limits on the EOS R5, somebody would have tested it already. But it turns out that the EOS R5 (and presumably EOS R6) overheating limits can be beaten by a simple clock change in the camera’s settings.
The folks at Hong Kong-based production company, Vision Rouge suggested the idea of changing the clock and a user by the name of yourboylloyd on the Magic Lantern Forums decided to see if it really was that straightforward. And, well, yes. It seems that it is.