In most raw files is an embedded JPEG of the image, made with all the in-camera settings. Auto-Matched Tone Curve in RT takes that image and the raw image, and calculates the difference between the two in tone, or more specifically, the tone curve it would take to make the raw image look like the JPEG. It doesn’t mess with other things like saturation.
So, the real test to see if AMTC is working is to compare the result with the embedded JPEG. in my RT 5.5 AppImage, the thumbnails look to be the embedded JPEG, someone correct me if I’m wrong, so that’s what you can use to compare to the AMTC result. So, AMTC benefit is directly reliant on how the OOC JPEG was produced.
If the DCP profile contains a similar curve to what AMTC calculated, then the results will look similar.
Again, all this tone curve stuff is just about tone, doesn’t take into account sharpening, denoise, saturation, or any of the other thing you could inflict upon your image…