You seem to be right about that the FDA does not yet recommend it as a treatment. However large studies do suggest its effectiveness like for example the study here:
https://www.cureus.com/articles/111851-regular-use-of-iverme...
https://jamanetwork.com/journals/jama/fullarticle/2801827
https://www.nejm.org/doi/full/10.1056/nejmoa2115869
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9308124/
In fact, I cannot find a double blind that supports the use of ivermectin to treat Covid.