Masking, hygiene, keeping a little distance, and staying away from indoor gatherings do in fact dramatically reduce the transmission of communicable airborne disease.
One side effect that dramatically demonstrates this is the suppression of seasonal influenza this past flu season. Popular Science summarized it this way:
Every year, around 45 million people get the flu in the US. This year, it was less than 2,000. Its an unprecedented low for flu season, and its a tribute to how well social distancing measures have workedthough they didnt stop COVID-19 entirely, influenza has virtually disappeared. This years case counts were two-thirds lower than the lowest year previously on record
https://www.popsci.com/health/flu-season-severe-2022/
Ponder that for a minute. 45 million during an average year.
Two thousand this year.
Scientific American has it graphically, dropping in Notrh America from 30,000 cases per week to, well, so low it appears as zero on the graph...under 100 per week for North America.
https://www.scientificamerican.com/article/flu-has-disappeared-worldwide-during-the-covid-pandemic1/
We have accidentally conducted a big experiment in controlling influenza with IMO stunning results. What we did to try to slow transmission of airborne communicable disease to control COVID worked, despite the finest misinformation available. Numbers can't lie.
Final thought, the over half a million deaths in the US happened with those (admittedly spotty, admittedly I enforced in some jurisdictions, admittedly ignored entirely by a segment of the population; we could have done so much better) measures in place to slow the spread of COVID. Now imagine the toll if we had had no mitigation whatsoever in place.