Canon hasn’t shared the way Canon creates its JPEG files.
What I have seen is that Canon Digital Photo Professional 4 apply noise reduction even if I set NR to 0.
If you want a camera manufacturer’s look, check here Do you want a straight out of camera JPEG style in darktable? Here we help each other
I created some of the styles there thanks to darktable-chart https://youtu.be/11nInNWJHWk