How long will this automated test take to be implemented?
Estimation of the effort involved is something that should be well done.
When you do it, there is much more to take into consideration that just writing the code.
The code will probably need to go through a few drafts.
It will need a lot of testing.
It will need refactoring.
Also, code review.
You should consider:
reviewing the test case
updating it (or creating a new one) if it is not suitable for test automation; test cases should be short, focused on 1 thing, independent
inspecting the pages for the element locators
writing the automation code (first draft)
testing the automation code
refactoring the automation code (second draft)
testing the refactored code
updating the test so that it works on
multiple environments (dev, test, stage)
multiple browsers (chrome, firefox, edge)
locally in a real browser and in a docker container
in the cloud grid
testing the updated test on
multiple environments (dev, test, stage)
multiple browsers (chrome, firefox, edge)
locally in a real browser and in a docker container
in the cloud grid
code review
implementing the feedback from code review
testing the refactored code
testing in the grid in parallel with many other tests
testing that the artifacts are created correctly (logs, reports, etc)
testing the integration with the test plan (Azure Devops)
Writing the first draft of code is just the beginning.