So I am looking for the name and the category of this body of water and landform. To me, it seems to resemble a coral reef, but there are some islands.
There has been a relatively recent study of coral reefs along the Saudi Arabian Red Sea coast, of particular emphasis on reefs between the cities of Haql and Yanbu, published in the paper The Present Status of the Red Sea Coral Reefs between Haql and Yanbu, Saudi Arabia (Hariri, 2012). In the article, they describe that in terms of Red Sea reefs:
The literature seems to use both Al Wajh and Al Wadj for the spelling.
A coral reef lagoon is that body of water that lies within an atoll (annular) reef or within a barrier reef. It is generally assumed that an appreciable depth of water is maintained within the lagoon, say 5-50 meters. Those reef platforms which have some shallow pools a few feet deep that show up especially at low tide have sometimes been called pseudoatolls or pseudatolls, and their pools thus “pseudolagoons” or “miniature lagoons,” but these terms are not recommended. The miniature lagoon of a faro (q.v.) is termed a “velu.” The terms “moat” or “lagoonlet” are often used for pools on platform reefs.
Coral lagoons are restricted to tropical open seas that provide the conditions necessary for coral growth. They are best exemplified by the roughly circular quiet waters that are surrounded by warm-water coral atoll reefs. Coral lagoons occur widely in the western Pacific, in parts of the Indian Ocean, and in isolated places in the Caribbean, mainly within 25° latitude of the Equator. Coral lagoons are of great importance to many island communities in the Pacific, particularly where they provide the only quiet water for use as harbours, although the passage through the reef into the lagoon is often perilous.