For those who are interested in ecologic observations, two Our World In Data graphs with case numbers colour coded by testing adequacy ( https://ourworldindata.org/epi-curve-covid-19)

One graph, (with Colombia and Argentina at the top) has countries that have mandatory masking.

....(most since March-April, but France and South Korea in May.) The one with the US at the top has countries that do not have mandatory masking (some places are debating it for public transport just recently). Then the next ...

...Do not have mandatory mask orders. We see out of control epidemics, and controlled epidemics on both graphs. Masks can not "mask" an ineffective response in terns of public health response with testing tracing and isolating, and public engagement in core measures....

So, I am wary of hanging our hats on masks as the intervention because they are, objectively, neither necessary not sufficient to control this disease. They are likely additive to a degree, possibly because they may serve as an ongoing reminder that things are not normal...

All successful countries do distancing, hand hygiene, testing and tracing, and some add masks. however, lots of countries with mask orders are still in deep trouble.
So, I'm now pondering the message of: LAYERS...

1) layered prevention:
keep contact numbers low, outside>inside, handwashing-distance-mask-shield, (more or less in order of evidence base).

And, also -
2) layered masks! Three layers, fabric combos including polypropylene layer or layers, well fitted. (If you're going to include surgical mask literature in your lit supporting masks we need cloth masks that have a chance at performing as well as surgical masks....)