Canon is not responsible.
Who can certify that the camera is not oberhrat after say 20 minutes ?
As camera has probably no tenperature sensor, and as 8k requires a lot of power processing, which translates to heat.
FOR ME is totally normal that canon decide to not allow more than N number of minutes of recording. And yoy cannot say that Canon is dishonest in this way.
Canon eos C models are bigger with bigger cooling solutions and indded dont have 8 recording.
SO STOP complaining to Canon for that, and enjoy more than 15 minutes of full 8k recording in a dslr camera, coño