There is no free lunch. Bulk create is no faster really than iterating over a list of primitives and creating Bubble Things out of them in the page or in a backend workflow.
However, as you’ve discovered, an API call can return to us an array. And you can just store that returned array. (Note: a Bubble list is not exactly the same thing as a JavaScript array, but it’s similar.)
And you can manipulate such arrays with List Shifter.