I hope some of this might help.
For _MG_0965.CR3, camera temperature is "CameraTemperature : 42 C" and higher sensor temperature will mean more noise. If the temperature in the room is cooler or if the camera had not been in use for very long the sensor would be cooler and there would be less noise. The _MG_0965.JPG file does not appear to me that it came out of the camera, but maybe was produced by converting an HIF file to JPG? The image would not have been so dark if the camera were set to sRGB and then one can use Canon DPP software to save a version as HDR PQ or as AdobeRGB color space when editing the CR3 file. What software do you use to edit the CR3 file?
ISO is 6400. With a small sensor, there is likely to be noise.
in Canon DPP software, noise reduction defaults to 11.0 chrominance and 11.0 luminance which is a lot of noise reduction and will likely make the JPG look better than the CR3 without noise reduction. The noise reduction will soften the image.
Peripheral illumination correction was enabled, and I suggest disabling it in camera and using Canon DPP or other software to do it when editing the CR3 file.
Digital lens optimizer defaults to 15.2 in DPP which suggests that it was enabled in the camera. More digital lens optimizer is possible with a lower ISO number. Setting "HighlightTonePriority : On" in the camera might result in more noise.
In the camera, you had set "HighISONoiseReduction : Standard" and "DigitalLensOptimizer : Standard" which will make the JPG look better than the CR3 file for some software used to view the CR3 file.
Auto lighting optimizer was off which is good.
