On top of that, individual experts still carry their own biases in their heads, and they lack any sort of editorial board to service the reader by separating knowledge from bias.
It’s easy for me to cast stones but I also have no answer. The best I’ve come to is to read broadly on topics you need to truly know and compare what you find in your sources. For less important topics just accept that you are likely off the mark and have much to learn.
The thing is, though, that the PPE handling requirements which practitioners like nurses and doctors are trained in, for working in a clinical environment with patients who are highly infectious or highly vulnerable to infection, are not the same as the PPE handling requirements for walking around a supermarket during a public health emergency. Public health usage of masks was not supposed to solve the same problems as masks solve in surgery or in infectious disease care contexts.
Experts are vulnerable to having highly specific knowledge about how something works in a very narrow domain, but overestimating how well that knowledge applies to even quite closely related nearby domains.
Rather, I thought the anti-mask advice came before it was known that masks helped. At the time this was the prudent advice: what they don’t want is people acting like the masks will fully protect them.
"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled."
I don't think there's a magical answer, but one approach I've found is to try to be a mini expert in a tiny, tiny slice of a bigger area (usually bridging over knowledge from some adjacent area I know). This means that I can then evaluate those who talk about this tiny area, and get a good baysian guess as to there broader expertise from there.
Some fields are such that they are hard to be expert in, but it’s trivially easy to verify expertise when observed. For example, playing tennis. It’s easy to identify a good tennis player even if you can’t play tennis at all. Another classic example is cooking. Even the most caveman-like philistine knows good food.
On the other hand, for some fields, verifying expertise (or ‘mastery’) is as hard as achieving it. Academic disciplines — particularly technical ones like science — are examples. In those cases, you probably have to rely on a trusted authority to verify legitimacy. Without that, you can’t distinguish the accomplished experts from the crackpot blowhards.
One can be a master in certain art, yet can't explain what's going on.
Think cooking: Many chef "searing steaks" to "keep juice in". It don't keep juice in, but it taste good.
Think language: Most native speaker can form grammatically correct sentence, but they can't really explain how. Yet many linguists, knowing how some languages work, keep bullshitting about another language.
Technical sciences are much easier than the social sciences. Social science is much more full of people who have no clue what they are doing than technical sciences, because technical sciences can be verified by experiments while social science is mostly about trust.
I'm not so sure. Identifying good talent is difficult when it comes to sports. There's an entire industry of scouts that try to find decent players ahead of the others. More so, they are tasked with finding out why a particular players is good. It's anything but trivial.
Not that one is trivial and the other is impossible. Of course, if you want to do any task well it becomes nontrivial.
So you are looking for someone with many years of work experience in being an IC or lead or CEO or a researcher with a lab or PhD in that domain with lots of papers in highly respected/ranked conferences/journals. In domains you have no idea about, you might need to first read a book or general article which links back to such experts/sources and then it is easy to find the cluster of those experts in that domain.