How to access nested properties of a type using keyof?

Question

typescript

I have a user type (example)
How can I convert it to userTarget type using generics?
The goal is to raise the keys to the first level from level 2. You don't need to go deeper.

type user = {
  user: {
    find: string;
    update: number;
  };
  account: {
    find: boolean;
    update: number;
  };
};

type userTarget = {
  user_find: string;
  user_update: number;
  account_find: boolean;
  account_update: number;
};