When i used Hooks useEffect with setInterval

I'm based on the React Docs write a setInterval in the useEffect,
i wants start a timer when app is mounted,
the recommended writing is:

const [a, setA] = useState(0);
useEffect(() => {
  const timer = setInterval(() => {
    setA(x => x + 1);
  }, 1000);
  return () => clearInterval(timer);
}, []);

When there is needs some dependency，i've been advised to use useState's callback function for avoid dependency, but when i needs another state b，it's the condition of a's self-increment.
like:

const [a, setA] = useState(0);
const [b, setB] = useState(0);
useEffect(() => {
  const timer = setInterval(() => {
    setA(x => {
      if (b > 5) {
        return x;
      }
      return x + 1;
    });
  }, 1000);
  return () => clearInterval(timer);
}, []); // dependency error, that required dependency b

To fix this problem, i combined state a and b，like:

const [c, setC] = useState({
  a: 0,
  b: 0,
});
useEffect(() => {
  const timer = setInterval(() => {
    setC(x => {
      if (x.b > 5) {
        return x;
      }
      return { a: x.a + 1, b: x.b };
    });
  }, 1000);
  return () => clearInterval(timer);
}, []);

Is this the right way to write it, or should I use useEffectEvent?