FullCalendar with Fiscal Calendar

I’m using FullCalendar for React. Instead of a regular calendar year, I would like to use a fiscal calendar. For instance, the current fiscal year (FY25) should begin on Sep 29, 2024 and end on Sep 27, 2025. The fiscal month of October should display 9/29 through 11/2. The current fiscal week should be 5.

Is there a way to change the underlying calendar object in this way?