If you can't do your rewrite in an incremental way, it is almost guaranteed to be a failure[1][2]. If you can make it two weeks without making any visible progress, you project is probably not on track for success. Granted, if your management thinks that they can get an entire multi-month project broken down into stories in advance, they have their heads up their asses.

[1] https://www.joelonsoftware.com/2000/04/06/things-you-should-...

[2] https://codeahoy.com/2016/04/21/when-to-rewrite-from-scratch...