Competition of airports in the sea

Kansai was the first airport built into the sea. However, the 5 square kilometre large artificial island quickly made negative headlines. The island began to sink, cracks appeared in the floor and water seeped into the buildings.
Despite the disaster in Kansai, other airports have been built into the sea in Asia. Incheon, the new airport in Korea, Chek Lap Kok, the new airport in Hong Kong, as well as Changi, the airport in Singapore. What do these new buildings look like? Are there similar problems as in Japan? What technologies were applied?