Thankfully these addons tend to be significantly larger and use profiles just as ElvUI.
All settins are stored in a local configuration file specific to a character (WTF/Account/Server/Character/SavedVariables).
#Transfer elvui profiles Patch
When the patch went live and I was able to get back into the game, I actually renamed the new Interface and WTF folders created by putting the word “new” in front of the name of each.
#Transfer elvui profiles update
That way you can always update your copies as you change things and reach a point where things are to your liking. The easiest way to safeguard them is to put those three copies into a folder and put that folder on your desk top out of the way. Once I have played comfortably for about 4-5 days with all the tweaks I want to make, I then log out and make copies of those folders and hang onto them. In fact I always keep a copy of them anyway in case something goes wrong. I actually did keep a copy of all three of my folders a week before the patch just in case.