The storyline is fine, everybody loves a shark movie - but you need a few characters you care about for it to work. And this movie actually has that, but the main character... wow, that's just cringey, and it ruins the whole movie. She doesn't come across as particularly resourceful and skilled at sailing or diving, and frankly... isn't that kind of the premise of the film? Ghenea is incredibly beautiful, and I have no doubt she's a stunning model, but this movie is more or less gratuitous shots of her features - and it just becomes cringey. If she can act, the director failed her miserably.
I looked her up, and can see that she had a cameo as Sophia Loren in House of Gucci. Now, that's a part I could actually see her rock, because it goes well with her femme fatale appearance.
Watch The Shallows instead for a female lead shark movie that's actually worth watching. Or even Crawl with the sharks being substituted for alligators instead.