Closer to a week or two, speaking as an actual software dev.
You have to first include the investigation into “how do we do it? What our are best options?” which is a day or two
Then the couple meetings as you go over your findings and get the sign off and approval that you can go ahead with it.
Then a couple days to implement it, write some tests for the code.
Another day for all the documentation to be added to Confluence, detailing all the above.
Another day or two for the code review process back and forth.
Another day or two for the QA testers to validate things are working.
There’s many many steps involved in going from “Idea” to “Implemented, reviewed, and tested”, and the human element in the back and forth stretches it out as you wait for people to take their lunch breaks, join the zoom meeting, the usual “your mic is muted mate” “oh jeez sorry” back and forth, etc etc…