The UX that make a difference are usually the ones you can’t see, read the book the design of everyday things or how to build habit forming products. The reason people become addicted to a product is usually not obvious, it’s more about a person being able to apply a psychological principle to their product in a practical way, when you do this successfully it’s very difficult to replicate cause you’d have to know why it’s designed that way to replicate it, that is why case studies are a big thing in UX design, it’s because the the thought behind the design tells you more about the design the success of a design than the design itself, you might see a design that’s doesn’t look good but is successful, you’d never be able to figure out why

Example, a lot of people have copied candy crush but yet candy crush is still the best of its kind, it’s mostly due to the little things they write after you loose a game, the way they present promotions (the timing) and all the factors you don’t see, the only thing you can copy is the promotion but the timing it why it’s successful which is the UX you don’t see. Just read how to build habit forming products