Well, there's no way that Losari (which is the most popular and central Makassar beach) is clean and pristine with clear water. It's more like a municipal pier with lots of food and concessions, but nobody swims there. It's a domestic tourism site that's mostly about restaurants, concessions, and other tourist attractions. There's no sand -- just rocks and pavement. The AI description is pretty misleading!
However, Pantai Biru and Pantai Tanjung Bayang are indeed much closer to the types of beach that you're seeking. There are many others like them, plus the small islands I mentioned.