Found another one at 8 million and is on an island:

https://www.quotenet.nl/vastgoed/qasteel/a62814634/luxueus-p...

This was in 2024 so likely valued around 9 million by now.

The home you listed at Funda comes in at €42000 per square meter which is unheard of for The Netherlands. Not even Amsterdam Center comes close. These homes are one of the most expensive pieces of real estate in the country.