You should perhaps read the studies you've linked a bit closer? When mentioned (as several of them are explicitly about masks in non-healthcare settings) - they all advocate for universal masking in healthcare settings specifically to limit the spread of Covid...
> Although more research on universal masking in heath settings is needed, it is the expert opinion of the majority (79%) of WHO COVID-19 IPC GDG members that universal masking is advisable in geographic settings where there is known or suspected community or cluster transmission of the SARS-CoV-2 virus.
> 1. In areas of known or suspected community or cluster SARS-CoV-2 transmission, universal masking should be advised in all health facilities (see Table 1).
> All health workers, including community health workers and caregivers, should wear a medical mask at all times, for any activity (care of COVID-19 or nonCOVID-19 patients) and in any common area (e.g., cafeteria, staff rooms).
> Other staff, visitors, outpatients and service providers should also wear a mask (medical or non-medical) at all times