Javascript Mistake — 1

users[index].emailVerified = cognitoUser.UserAttributes[1].Value;

UserAttributes[1] — to avoid mistake you should not specific index and code should look like this.

Object.keys(cognitoUser.UserAttributes).forEach((index) => {
   // assigning cognitoUser.UserAttributes[1].Value
  if(cognitoUser.UserAttributes[index].Name === 'email_verified'){
    users[index].emailVerified =     cognitoUser.UserAttributes[index].Value;
   }
});

Using object.key looping through the array and look for which JSON field you want.