How much of that was known then?
Most of what's known today, was known by late srping/ early summer of 2020. But nobody in power was listening to the right people. They were carried away by covid hysteria/ fear/ power.
Barely transmitted outdoors.
6' is an arbitrary distance.
Indoors, HEPA filters and fresh air lowers the transmission.
Obese people are at higher risk of complications.
Diabetics are at higher risk of complications.
Older people are at higher risk of complications.
Young, healthy people are at very low risk of complications.
Treat the pneumonia like ARDS; use respirators correctly.
Natural immunity from having had it, is protective.
So schools and shuls can reopen for young, healthy people. Older teachers, especially with health issues, shouldn't be there. (Until they get the vaccine.)
Outdoor spaces should be open with families staying a bit separate from each other.
Old or otherwise vulnerable people should self quarantine to the degree that they can. No indoor visits or hugging from the more exposed family.