A manual backup is also possible and easy:
Be sure to logout before!
Just copy the whole users/.../documents/Elder Scrolls Online/live folder to another place and you got all addons, SavedVariables, screenshots etc. backuped.
You'll find the folder like explained here:
https://www.esoui.com/forums/faq.php..._howto_install
You can also manually copy the sub-folders like AddOns, SavedVariables if you do not want to backup all data inside the live folder.
Do the same for the PTS folder if you play on the public test server as well.