Optimization problem: Mongoose aggregate() doesn't return Model objects

Question

I use a Model that, simplifying a lot, has some custom functions such as:

let MySchema = new mongoose.Schema({
  email: {type: String, required: true, unique: true},
  firstName: {type: String},
  lastName: {type: String},
  status: {type: String}
})

// Model custom functions
MySchema = {
  login(email, callback) {...},
  logout(email, callback) {...},
  ...
}

// This works
MySchema.findOne({email: userId}).then(user => user.loging())

// This also works
let user = await MySchema.findOne({email: userId})
user.logout()

... apply AppUsers as mongoose model of such Schema

// This works
let users = await AppUser.aggregate([
        {
          "$lookup": {
            "from": "stg_appusers",
            "localField": "email",
            "foreignField": "email",
            "as": "stg"
          }
        },
        {
          "$match": {
            "stg.email": {
              "$exists": false
            }
          }
        },
        {
          "$match": {
            status: "expired"
          }
        }
      ]).exec()

// At this point the aggregate() returns correctly what
// I need from the query (difference but two collections)
// as array, but each element of the array is not a Model
// for which I can invoke my Model custom functions
users.forEach(user => {
  user.logout() // ⚠️ This doesn't work: TypeError: user.lgout is not a function
})

// I am using following as workaround...
users.forEach(user => {
  AppUsers.findOne({email: user.email}).then(userFetched => userFetched.logout()) // This works, but...
})

Overall, the code is working by using AppUser.findOne({email: user.email}).then(userFetched => userFetched.logout()) but clearly is not performant: after the aggregate() I am not able to use the logout() function, so I have to call a find() for each user returned from the aggregate().

Calling findOne() for each user found by the aggregate() would be fine, but the two Collections have similarly more than 1.000.000 users and the findOne() takes too time.

Why I can't call users := user.logout() where users is the result of the aggregate()?

---

Update from comment:

[
  {
    _id: 6040fd38191f66368dfe4ca0,
    status: 'active',
    email: 'some.one@coolcompany.com',
    firstName: 'some',
    lastName: 'one',
    ... many other fields, such as in the findOne()
  }
]