I'm not sure what you think the "literal" meaning of "job" is.
(Skip the references to the proper name Job.)
Definition 1 is regular work done in exchange for payment, like, "His job is working in a widget factory."
Definitions 2 and 3 both refer to specific tasks that a person might undertake, as in, "After I do the laundry, my next job is washing the dishes."
Your example falls under definition 2. Perhaps you are thinking that the "literal" meaning is definition 1? But definition 1 is no more literal than definition 2.
There are contexts where it might be ambiguous. Like if someone began a conversation by saying, "My job is washing dishes", it wouldn't necessarily be clear whether he meant that he is employed by, say, a restaurant as a dishwasher, or if he means that at home he washes the dishes while his wife performs some other household chore. In such a case, you could use a different word, like "occupation" or "profession" versus "task" or "assignment". Or use additional words to make it clear. "My job at home ..." versus "I am employed by ... to ...".