PrivatePrefrences.json and Prefrences file are for local settings.
F.e How many times SU is started, where the Folders are positioned, what Plugins are used. Window settings.
A lot of them you don’t want to have them shared. So, don’t share the json file, or you have to have exactly the same setup and settings, read ‘Like a Clone’.
You could share the sharedPrefrences.json, as far as I can see. This one contains global acceptable settings like color of the x-y-z beams among other usable global settings , like shortcuts. I did create a ‘ln’ to that file, because I did not see, for now, any other option to share that file.
You could do a one time copy from both of those json files to the other device and changes what is needed in SU.This, like the path info works, when, like John wrote, the user names are the same.