Stack appears to accept a ref prop based on the TypeScript types, but this ref is not actually bound to the underlying element:

export function Example() {
  const ref = useRef<HTMLDivElement>(null)

  useEffect(() => console.log(ref.current))

  return <Stack {...props} ref={ref}>contents</Stack>
}

If Stack correctly forwarded its ref, the console would log an HTMLDivElement instance. However, it instead always logs null.