That, like most aspect of art and creativity, is a skill that takes practice. For writing specifically, you’d have to read more books, watch more films, and generally study how others do it. Eventually you’d be able remix all your previous experiences and other people’s work into something new and your own. It may come easier to some compared to others, but with practice everyone can come up with great ideas.
For paintings, at least for me, it’s less of deciding what the art to represent and more like I have something in my mind that I need to get out into the world, and painting is just one way of doing it. It’s less “I want to put something in the oven, but what?” and more like “I want chicken. Should I roast it in the oven or deep fry it?” if that makes sense lol
There are dozens of us!