If you want to start with the Adobe Standard color, but remove the Tone Curve that increases contrast in the midtones and compresses highlights, you can change the Tone Curve embedded in the DCP camera profile to a linear tone curve. You can use the DNG Editor, but the faster and easier way is to use EXIFTool with the following command:
exiftool -ProfileToneCurve="0 0 1 1" -ProfileName="YourNewProfileInternalName" -o NewProfileName.dcp OriginalProfileName.dcp
This will create a new DCP profile based on the original, but the tone curve contained in the original will be changed to a linear one in the new profile (connecting point 0,0 with point 1,1); likewise, the internal name (the name that gets displayed inside of the ACR and LR interface) in the new profile will be changed to "YourNewProfileInternalName." The argument after the -o flag is the filename you wish to give the new DCP profile and the final argument is the profile you are feeding exiftool as the basis (for example, Adobe Standard for your camera).
On a Mac, the Adobe Standard Profiles can be found here:
/Library/Application\ Support/Adobe/CameraRaw/CameraProfiles/Adobe\ Standard
And you would put your new linearized profile in your user profile folder here:
/Users/<your username>/Library/Application\ Support/Adobe/CameraRaw
Removing the Tone Curve and linearizing it will remove the contrast in the midtones and expand the highlights, resulting in a flatter file.
See:
https://www.rawdigger.com/howtouse/overriding-raw-converter-default-adjustments-settingsand take a look at the comments, where this technique is discussed (using exiftool).
Have fun!
Kirk