Perhaps a small help link to the FAQs would solve the problem? If the transfer fails, most users would surely click on it and learn about the alternative option.
In my opinion, the profile switcher is the “natural” place for the backup feature. New profiles are created and deleted there. Therefore, it would make sense to be able to create backups there as well. Besides, a backup isn’t a setting.
Maybe it would also make sense, for marketing reasons and to improve security awareness, to rename the “Add Second Device” feature to “Add Additional Device?”