context api is mostly used to pass the data from one state to another state and it just make. It is determined as the value passed to the closest SomeContext.Provider above the calling component in the tree. If there is no such provider, then the returned value will be the defaultValue you have passed to createContext for that context. The returned value is always up-to-date. React automatically re-renders components that read some context if it changes.
I think Context Api is best alternatives to pass data over the redux toolkit such that it handles all situation of the passing or calling of data in which the transfer rate is best covering the data.

if there is not such Context provider than it will pass accept the default value you have to pass the context you provided The returned value is always up-to-date. React automatically re-renders components that read some context if it changes.

Updating data passed via Context Api
often you will change context to change over time To combine it with context combine it with state variable in the parent component and pass the current state down as the context value to the provider.