It's not standard because you can just use filters.
Keep in mind the filters have to be able to filter the dead pathogens anyway (usually same size) or else you are breathing them, which isn't great either. Better than live ones for sure, but not great.
As for UV, you can add it to either residential or commercial easily (some preschools and schools I've visited added them in the past year). It doesn't make sense to install in every room, as you say.
Keep in mind the filters have to be able to filter the dead pathogens anyway (usually same size) or else you are breathing them, which isn't great either. Better than live ones for sure, but not great.
As for UV, you can add it to either residential or commercial easily (some preschools and schools I've visited added them in the past year). It doesn't make sense to install in every room, as you say.
On ozone, see https://www.epa.gov/coronavirus/air-cleaners-hvac-filters-an... and the section on ozone.