You are correct. The ship has not been announced yet. But hundreds of booked guests on the 2024 W.C. have done a Future Cruise Request for 2025 W.C. already. To lock in getting first dibs on the same cabin they have on 2024 W.C. including us.
If you do the math the Zuiderdam would bring in the most booking dollars because of the selection of state rooms it has compared to the Zaandam. Based on 1500 guests.