Royal Society have just published their report on the effectiveness of Non-Pharmaceutical Interventions in Covid.
https://royalsociety.org/topics-policy/projects/impact-non-pharmaceutical-interventions-on-covid-19-transmission/

On Masks:

#Covid #RoyalSociety #NPIs #pandemic

The Royal Society’s programme on the impact of non-pharmaceutical interventions on Covid-19 transmission | Royal Society

The Royal Society has launched a new report investigating the evidence of the impact of non-pharmaceutical interventions (NPIs) on the transmission of the SARS-CoV-2 virus since the start of the Covid-19 pandemic.

Studies about ventilation seem much less clear cut:
Generally seem to support the use of social distancing and lockdown to reduce transmission rate.
Mass testing seems to reduce incidence. Contact tracing studies were mixed and there seemed to be few studies on the impact of isolation, though isolating cases before results of tests seen as effective to reduce household transmission.