The best sources are public health authorities like the WHO and CDC. They have consistently made careful and measured statements, been fairly accurate, minimized scaremongering and speculation without understating the seriousness of the situation, and issued useful recommendations. Most people would be better off following these authorities directly and ignoring other coverage.
Do you have links to that data? For you to make this claim you'd be able to link to a meta-analysis or a well run RCT.
Early on the WHO's biggest concern was that panic buying would lead to mask shortages for health care workers. If you have to choose between an unmasked public and unmasked health care workers, having the public go without is definitely the better option.
So IIRC around March they issued the guideline - if you feel sick, wear a mask, otherwise don't. And it made sense in context, because after masks worn by health care workers, the infected are the next most effective place to deploy masks in terms of protecting public health.
Eventually mask supply increased because everybody started producing them. The WHO then changed its recommendation to "everyone should wear."
So I don't really think the WHO did anything wrong here. But because of the one-sided way it was portrayed in the media, the negatives got amplified and we ended up with "WHO NWO EXPOSED MILLIONS DEAD!! BILL GATES EUTHANIZES AFRICA CONTINENT GLOBAL ELITES KILLING VACCINE PEDOPHILIA" all over YouTube. Again.
Any mention of masks is conspicuously absent from their "what you should do to protect yourself" list. More than that, they stamped a giant "INCORRECT" over a social media image which, although it probably did get some details wrong, was much more on the right track than WHO with "Wear a mask everywhere!"
There are a few that don't show any benefit to wearing masks.
What should CDC / WHO / etc do then? They have evidence, it's good quality, but it doesn't show any benefits to masks wearing. Should they tell people to wear masks? We didn't know at the time whether this would cause people to drop social distancing or not. There was a real risk that people would wear masks, but drop isolation.
I feel you should be linking to a study showing that telling people they must wear masks to go out would reduce social distancing. To me, the requirement to wear a mask only reinforces the danger.
Newspapers are at best a secondary source, not primary.
Academic journals are intended to disseminate articles to be subjected to peer review, which means they are intended to spark discussions over observations among researchers in the field. This means that, with the exception of academic fraud, it's expected that their content doesn't reflect solid understanding of the issues involved. Otherwise they would be pointless as scientific papers.