We now know that masks were barely effective or not effective at all. They could even be net negative by causing people to take more risks.
Isolating was the only way. A lot of elderly in the UK did this successfully and never got covid. Lockdowns, masks and schools closures did not affect the spread significantly. We know this because Sweden did not mandate these things and had about the same amount of people getting covid until vaccines arrived. The benefits were that Sweden had less mortality from other causes.
A well-fitted N95 mask is almost perfectly effective. I have been in a number of situations where my maskless companions got COVID but I (wearing a 3M Aura) did not.
Isolating was the only way. A lot of elderly in the UK did this successfully and never got covid. Lockdowns, masks and schools closures did not affect the spread significantly. We know this because Sweden did not mandate these things and had about the same amount of people getting covid until vaccines arrived. The benefits were that Sweden had less mortality from other causes.