A new open-label randomized clinical trial study shows very good results in treating covid patients with Bromhexine hydrochloride (a derivative of Bromhexine)
https://bi.tbzmed.ac.ir/Files/Inpress/bi-23240.pdf
The candidate drug, Bromhexine Hydrochloride, is cheap (20c per 8mg pill), widely available (mass-produced over-the-counter), and has few side effects. It just thins mucus.
It was patented in 1961 and came into medical use in 1966
Pic related is how it is supposed to work vs Covid