Unfortunately, there is no "import courses" feature in Forma. As far as I know, only some commercial LMS' (such as Blackboard among others) offer this kind of migration feature and are able to restore a backup created in Moodle.
Of course, you can import users (from a .csv), tests (in GIFT format), Scorms. But you cannot import "courses".
We have some experience in migrating users and courses (and the user status and completion dates) from a different LMS to Forma; in those cases, we build a script and we run it on Forma to restore the desired situation in the best possible manner.
The same is probably true for Joomla and Wordpress: I don't think you can easily import a WP website into Joomla.
There is no course import or course export feature, so you cannot back up Forma courses offline.
What we did was creating a .csv file with a long list of fields (course_id, course_name.....): the script was used to automatically insert records in the (many) relevant database tables, thus creating the courses from the old LMS (I don't remember what it was, but it's irrelevant), replicating all the old course subscriptions and the users' completion date.
In that case, the issue was not replicating the course (actually, we didn't re-import the Learning objects) but replicating the users' situation from an old LMS to a new one.
I understand your issue is different (importing the courses, the LO's and the course settings), right?
I don't know how many courses you need to migrate, I would consider doing it manually + importing the tests as I described above (GIFT format).