This has nothing to do with hindsight.
We've known for decades that hand sanitizer (and antibiotic soap) kills off the beneficial bacteria on your hands, and also dries out skin, increasing the percentage of pathogens that survive contact with skin, and also increasing the percentage that manage to get past skins' protective barriers.
We also knew that coronavirus was airborne well before 2019.
The medical and microbiology/virology communities provided advice that was the exact opposite of what the epidemiologists suggested, and were ignored.
Epidemiologies are closer to being historians or sociologists than doctors, so letting them run the show made no sense, and, in hindsight, what was obvious at the time turned out to be correct. The lockdowns were absurdly expensive, created massive secondary public health problems, and didn't save as many people as the approach dictated by conventional wisdom would have.
Conventional wisdom said we should figure out which people were most vulnerable (the elderly, obese and people with chronic medical conditions), and aggressively quarantine just them. That would allow covid to spread through the rest of the population in a month or two, and wouldn't require the entire economy to shut down. Instead, something like 5% of the workforce would call in sick for a month or two.
At this point, the excess mortality from the pandemic is above the expected mortality rate for low risk groups, so, in hindsight, we now know for sure that we should have listened to the medical community, and the findings of the (now retired) epidemiologists that studied the last pandemic.
Having more supporting evidence now doesn't change the fact that all of this was obvious at the beginning of the pandemic, but that it was ignored / actively censored by our leaders.
Anyway, at the end of the day, covid is a strain of the common cold, not some crazy alien pathogen that we have zero experience with. Also, humans have dealt with dozens of pandemics during recorded history. The whole "this was a brand new thing we had no experience with" argument just doesn't hold water.