It opens up in CameraRAW 13.0.2 with the ColorChecker Mini image in it.
I select the Adobe Standard profile (seems to be the "best").
The results of which is shown in the “No adjustments of any kind” Group in the linked Photoshop document.
I carefully noted the resulting RGB values for each gray patches, shown in red in the linked Photoshop document.
Compared to the “ideal” – see Ideal group in the linked Photoshop document – it’s a far cry?
So, on with some needed Curves adjustment.
Best I could do is shown in the green numbers, in the linked Photoshop document.
Close enough but I wonder if I can do better?
FWIW, I also experimented with creating a DNG profile using the DNG Profile Editor.
But the "Tone mapping", as far as the Munsell gray patches are concerned still needs a fair amount of work. See below.
The cursor, here, was on the N5 patch (below Yellow) and the RGB values were 150,151,150, very neutral, but they ought to be around 120 instead, to better correspond with typical sRGB or AdobeRGB ColorChecker RGB values, in my humble opinion.
Once I got the "converted" RGB image in Photoshop, I saved the image in TIFF format and proceeded to create an ICC input profile using i1Profiler on Windows. Once I got the profile, I went back to Photoshop and Assigned the profile to the image. The results were much, much better than having only used the custom DNG profile.
Got a average DeltaE76 of 1.42 with a max of 3.87.
I don't suppose there would be a way to get this close through only using the DNG profile?
I must be doing something silly wrong but I can't see it. I spent a lot of time surfing the web and watching YouTube videos but that's the best I could see.