Saudi Arabia’s planned futuristic mega-city known as NEOM announced on Sunday the opening of its “first physical showcase”: a luxury Red Sea island featuring restaurants, hotels and yachting berths. The opening of the island, known as Sindalah, comes amid persistent doubts about NEOM’s viability and ahead of a major investor forum sometimes referred to as “Davos in the Desert” which will begin in Riyadh on Tuesday. “NEOM is committed to supporting the Kingdom’s new era of luxury tourism, with the opening of Sindalah,” chief executive Nadhmi al-Nasr said in a statement. “NEOM’s inaugural destin…