I honestly don't know how people navigate in society without this being plainly obvious to them. The number of people who believe most claims can be checked to any level of certainty is genuinely worrying and highlights a fundamental lack of critical thinking within our society, and therefore democratic process.

As you say, most of the time these aren't "facts", but usually opinions or hypotheses based on a subject interruption of some data. The truth is even if 99% of the evidence we have today suggests masks work, this doesn't mean masks work, just that it's very likely they do assuming there isn't some bias in the research. The reason I mention bias is because it's simply true that in the past research on things like contentious subjects like climate change, smoking and various diets have been biased by corporate interest.

I think the problem we have with misinformation today is less that people sometimes believe the wrong things, but they believe the wrong things with high levels of conviction and passion. The first step in the solution to misinformation in my opinion should be to promote an attitude similar to yours -- one of general scepticism and an openness to new information and beliefs.