I want to extend the function argument type by adding a function with any name to each object and return it, but i am facing a problem with naming the key of the added function

export type Expand<T> = {
  [K in keyof T as K | string ]: T[K] extends { [K in string]: unknown }
    ? ExpandData<T[K]>
    : T[K] | ((p: T) => T);
};
type ExpandData<T extends { [K in string]: unknown }> = T | Expand<T>;

export const create = <T,>(params: Expand<T>): Expand<T> => {
  return params;
};

type ICreate = {
  param: {
    first: {
      value: number;
    }
  }
}
const result = createState<ICreate>({param: {
  first: {
    value: 1,
    change: (val)=> val,
  }
}})

 



// result.param.first.value error
// result.param.first.change error

How to do this correctly?