useField() returns FieldRenderProps. It will manage the rerendering of any component you use it in, i.e. the component will only rerender if the field state subscribed to via useField() changes.

Think of useRef as a useState that does not trigger a re-rendering of our component.

In the two years that I've been working with React professionally, I've never come to a point where I needed to force a re-render. I encourage you to read the article from the beginning if that's what you're here for because usually there's a better way of dealing with React components that aren't updating.