@jammmy Congrats! Are you currently in Au? What Visa are you holding? Before you withdraw or cancel any Visa application make sure that you have a valid visa that lets you stay lawlfully here in Au. Are you staying here on a Bridging Visa (from the 457 ) at the moment? If you will cancel the 457 , it automatically cancels the Bridging Visa that comes with it which will leave you unlawful IF you are staying here on that Bridging Visa.
Don’t do anything in haste. I don’t think telling your employer will help at this stage especially that it was just lodge a week ago. I think it’s best to tell them once you have submitted your PR application. Read your contract as well and see if you’re breaking any of the clauses.
Lastly, before you lodge your PR application, make sure that you have uploaded all the needed documents for a chance to a Direct Grant otherwise it will be a LONG wait if you missed to upload something.