It's a fact that it is a Novel virus. It is a fact that nobody knows all the answers absolutely yet. You might want to read the linked report that summarizes studies into transmission of Covid.
https://www.publichealthontario.ca/-/media/documents/ncov/covid-wwksf/2021/05/wwksf-transmission-respiratory-aerosols.pdf?la=enAmongst conclusions from the report:
"SARS-CoV-2 is transmitted most frequently and easily at short range through exposure to
respiratory particles that range in size from large droplets which fall quickly to the ground to
smaller droplets, known as aerosols, which can remain suspended in the air."
"There is evidence to suggest long-range transmission can occur under the right set of favourable
conditions, implicating aerosols in transmission."
"The relative role of large respiratory droplets versus smaller droplet particles in short-range
transmission is challenging to quantify. Their contributions to a specific case-contact interaction
vary based on contextual factors including source/receptor characteristics (e.g., forceful
expulsions such as singing, coughing, sneezing; viral load) and pathway characteristics (e.g.,
duration of exposure; environmental conditions such as ventilation, temperature, humidity,
ultraviolet light; source control; and use of personal protective equipment)."
"Translation of this summary into control measures needs to take into consideration other
information, such as evidence around the effectiveness of control measures to date. Several
control measures applied together in a layered approach are likely to be effective irrespective of
the relative contribution of droplets or aerosols, including achieving high vaccination coverage
and avoiding the “3 C’s” (closed spaces, crowded places and close contact)."
Re the last conclusion, it is also a fact that the wearing of masks will limit the spread of droplets and aerosols from an infected person who is coughing, sneezing, singing or shouting. It is less clear how much masks protect the receiver of aerosolized virus, so best to try to limit the spread at the source person. It is also a fact that we often don't know who has the virus and is contagious. It seems so easy and probably self-protective to wear a mask if there is a need to enter a 3C space.