It seems to me that we should immediately move to massively increase production of hydroxychloroquine. If it turns out to be part of a solution, great. If not, I doubt that more than a tiny fraction of the total resources dedicated to the pandemic would have been used up by the effort. There is no time to take things slowly in our situation. In any case, from what I've read on places like r/medicine, many people who have access to hydroxychloroquine have already begun to hoard it. So one way or another, if we do not ramp up production there will be trouble.
Hydroxychloroquine has been around for decades, so it's not like we would be jumping into a total mystery about its side effects.
It seems to me that, whether hydroxychloroquine ultimately turns out to be effective or not, it is the closest thing we have right now to something that might prove to be a very helpful medicine.