Sorry I don't have a full answer for you, but just to help with this part: How are you looking for this pathway? If by clicking through Finder, do you have hidden files and folders shown on your computer? For the most part, folders that start with .* are hidden by default. To toggle the display of hidden files and folders you can press Command+Shift +. (more info here).
You can also get there by using the Go To Folder interface in Finder. The shortcut to access that is Command+Shift+G, or from Finder go to the "Go" menu, and select it from the dropdown. Once that opens, you can paste/type in ~/.config/rstudio, and it will take you there.