I did some research on this a while back, and posted what I found then. I tried to look to peer reviewed epidemiological studies, not news reports or opinions. What I found was that the answer is not clear. It does appear that if people who are sick wear a mask they are less likely to spread the virus, or any airborne disease. The evidence showing the protective effect on well people was less clear, there seemed some evidence that masks could help, but not a whole lot. I could find nothing indicating harm of masks.
Wish the answer was clearer, but its not and that's often the way of the world. I wear a mask when asked, and on occasion when not, but I don't get obsessive with it one way or the other. I live in a rural area where masks are rarely seen.
I know some masks are better than others at filtration, but that is not the whole story. Dispersing breath and just impaction rather than filtration can be beneficial in lowering exposure. Part of why I think the epidemiological studies are more informative, rather than looking at the mechanisms of how masks work or don't they look at the question as to if people who mask are less likely to spread or get the virus. However the epidemiological studies are more expensive, take longer, and can be harder to interpret, so they are not as common.