That's what the very-rarely-used `useImperativeHandle` hook is for - exposing "instance methods" from function components:
https://reactjs.org/docs/hooks-reference.html#useimperativeh...
useRef was designed for this purpose: https://reactjs.org/docs/hooks-reference.html#useref
If you ran into something that isn't quite covered by this hook, I'm also curious! Can you write a minimal example in codesandbox and share?
One thing we haven't been able to replace, though, are classes that depend on refs. How to do this, since there's no instance with functions like there are with classes?