Death from COVID, and other pneumonic (pulmonary) diseases, can be commonly a result of secondary infection by bacteria. Our bodies are not the best at handling two different types of threats at the same time. See https://www.nature.com/articles/s41598-021-92220-0 for instance.

P.S. Note that the situation was unclear in 2020-2021 -- for instance from a quick lookup see https://pubmed.ncbi.nlm.nih.gov/34354682/. So patient management was different per region -- as it was a guess.

Secondary infections of bacterial pneumonia were common with COVID iirc.

When I was in Peru, they kind of prescribed antibiotics for everything. Persistent cold? Antibiotics. Like that.

Source: lived there with Peruvian partner for 18 months.

Some of the antibiotics have also proven antiviral and/or immunomodulatory effect, e.g. azithromycin [1] or levofloxacin [2].

[1] https://pubmed.ncbi.nlm.nih.gov/34015317/

[2] https://pubmed.ncbi.nlm.nih.gov/32546446/

I think some of those 'kits' countries were distributing to people early-on (before the vaccine) contained stuff like doxycycline.