I have been on hydroxychloroquine since 1989 with no problems.
Long term, if your dosage is too high, it starts to build up in your eyes and clouds your vision. If this happens, it is reversible by lowering the dose. An eye Dr appt every year will find this quick enough.
My question is, will people already on it have less symptoms and shorter recovery?
That question remains to be answered. but, in countries that have endemic malaria, the incidence of covid 19 are much much lower. Prevailing thought is that with the majority of the population being on antimalarial drugs, it has an effect on the virus's ability to take hold.