When I say that COVID is on a technical level fairly easily solvable, we just choose not to - it's things like these that I'm thinking of:
https://www.mpg.de/16075350/1127-chem-ventilation-made-easy-152990
> A simple ventilation system removes 90 percent of respiratory aerosols which potentially include coronavirus particles, from indoor air […] The design is very simple and was implemented using DIY store materials worth about € 200.