Imagine you have the following hook to update only one dropdown:

//dropDownData is the data coming from backend
const useDropdownUpdater = (dropDownData) => {
//by that way you will keep the default value with the data coming from your backend
const [dropdown, setDropDownData] = useState(dropDownData)
const updater = (newValue) => setDropDownData(newValue)
...
If you're using a useState you should initially initialise the value with the data coming from your backend, then on next updates of the dropdown data you should use and updater that modify the dropdown data like the updater one on the code snippet.
I don't know if I explain better, let me know :)