Within the Preferences folder, you’ll find Steinberg/Cubase .plist files, but you’ll also find a Cubase 10 folder which has files within it that are not .plist. One of these files is called Key Commands.xml. I suggest you copy that file and back it up like you would your Profile within Cubase (after testing this myself, I can say that the Profile DOES NOT retain the key commands).
Since this is a Cubase 10 folder, it should be okay to leave it alone (but backing up the Key Commands file is just a plus), and deleting the .plist files that are outside this folder will not affect it. If I’m not mistaken, you could try replacing the existing key commands file in the 10.5 folder with this one that way you can automatically have your key commands ready.
I think everything related to the workflow is stored in the Cubase 10 folder within the Preference folder, which as I mentioned, does not contain .plist files.