The 7D had similar heating issues when it was used as a video production camera. Production companies dealt with it by keeping multiple copies (3-4) of the body in rotation. In production environments under "hot lights', even the 5D Mark II had to be rotated using multiple bodies when used as a primary production camera (such as with some episodes of the TV series "House").
Canon is known for reliably delivering what they promise. They've always been more up front about what limitations their cameras may have in specific scenarios, and such cameras almost always deliver more than Canon promises in such scenarios, not less.
Canon has made it very clear that the R5 is not intended as a primary "A" camera for productions that require extended shooting intervals. It's meant to be a supplemental camera in such scenarios, for use as a "B" roll camera (which doesn't need to be able to record indefinitely), or as a specialized slow motion/special effects camera (which, again, does not require being able to record indefinitely), or as one for shots with tight space constraints (which again don't normally last for extended time periods).