I have looked online and all I can find is a reference to a study that is to be done and recommendations from HVAC companies that I purchase a service contract. I have not found the study/report you read that attributes evaporator corrosion to cleaning something with bleach.

If the tiny amount of vapors from diluted bleach that might rise out of a 3/4” (1/2”?) drain line that provides zero airflow can cause corrosion then certainly the eye-burning concentration of bleach in common household cleaning products drawn directly through the coils will cause corrosion. When it is recommended to stop using bleach products to clean bathrooms THEN I might begin to be concerned about adding a 1/4 cup of vinegar to a gallon of water before pouring it down a plastic drain line.

No one is telling you to stop pouring chemicals down your condensate line. Just trying to confirm what most HVAC companies are now recommending to do and what not to do. If you feel you know more than them, then that’s fine, go at it. Although I understand your logic I also understand what an experienced professional is saying and in my case, right or wrong, I’m not going to take that chance. Hot tap water once a month has worked for me and my neighbors for a very long time so why would I gamble using bleach or vinegar for example?