Please shoot something with lots of fine detail and varying colors at infinity focus (trees with autumn colors are the best, check my youtube video I posted in this topic), both h.265 and ProRes. When it comes to h.265, the higher bitrate the better, and ProRes should be 422. UHD or higher resolution is fine.
When comparing both cameras, please use the same scene with the same settings. F-Log and/or F-Log2 please.
I know I ask a lot, but if you have other cameras as well, Canon/Sony/Panasonic, it would be nice to see them as well. The issue might not be obvious until you start to compare it with other cameras.