Definition of janitor:
one who keeps the premises of a building (such as an apartment or office) clean, tends the heating system, and makes minor repairs
https://www.merriam-webster.com/dictionary/janitor
a person employed to take care of a large building, such as a school, and who deals with the cleaning, repairs, etc.
Or
a person whose job is to clean and take care of a building
Janitors are only employed in large, expensive apartment buildings. Single family homes don’t use them, nor do cheaper apartments. So that’s not really descriptive of a landlords job at all.