Use an interval that you can pause
An interval with pause can replace most use cases for more complex packages like react-countdown.
Pros
You can use any time and date library you want (date-fns, day.js, moment.js). Extremely small bundle size.
Cons
You must perform all date calculations and formatting.
It ends up offering little more than an implementation of many useEffect()
tutorials. Why add a dependency for so little code?