according to the internet this ship “Hero of the Seas” is 250,000 deadweight tons
For comparison, the USS Gerald Ford is 100,000 DWT.
I think you’re mixing up Hero’s volume (gross tonnage) with the Ford’s weight in water (displacement). The Hero’s displacement is about 115,000 tons.
Also, I think DWT is a measurement of everything a ship carries and not its own structural weight. But GT and DWT aren’t used for measuring warships, just displacement. And displacement isn’t often used to measuring cruise ships.