Comment by Ethee

Except that's not really true. Take OPs example of the search bar, in most shops as a UI/UX designer you put a search bar on your figma page and hand it off to the engineer who then implements it. It's entirely up to the engineer how the search functionality is going to work, am I going to query my backend on every keypress? Depending on how big your database that could be anywhere from 50ms-1s for a response PER KEYPRESS, which is exactly OPs problem. I don't see how the UI/UX designer is going to fix or solve that.