“Isn't ivermectin approved for animals to kill parasites or bugs or something similar?.”

Ivermectin, oral and topical, is FDA approved for use in humans for a number of parasitic infections and skin infections/disorders. I recently prescribed it for refractory scabies and it worked very well, no side effects reported.

“Leronlimab: s/c and m/m and longhaulers and HIV, cancer, etc., etc., etc.”

Leronlimab is not approved for any of these indications, only in trials at the moment.