Mongodb join elements inside of an array

Question

So basically what I'm trying to achieve is to get tickets from a concert. every ticket has a seller ID which I want to join with the collection users.

This is the query I have, to get all the tickets from a concert:

let concerts = await Concert.aggregate([
    {$lookup: { from: 'artists',localField:'artistId',foreignField: '_id',as: 'artist'}},
    {$unwind: "$artist"},
    {$lookup: { from: 'tickets', localField: '_id', foreignField: 'concertId' , as : 'tickets' }},
])

I have tried everything to join the seller ID inside the tickets with the user collection, but nothing has really worked out so far.

Here are my schemas:
Concert:

const ConcertSchema = new mongoose.Schema({
    title: String,
    date: Date,
    address: String,
    genre: String,
    artistId: mongoose.Types.ObjectId,
}, {timestamps: true});

Ticket:

const TicketSchema = new mongoose.Schema({
    type: String,
    price: Number,
    redeemed: Boolean,
    redeemedAt: Date,
    sellerId: mongoose.Types.ObjectId,
    buyerId: mongoose.Types.ObjectId,
    concertId: mongoose.Types.ObjectId,
}, {timestamps: true});

And User:

   var UserSchema = new mongoose.Schema({  
        username: String,
        password: String,
        email: String,
        walletId: mongoose.Types.ObjectId,
    }, {timestamps: true});

This is what i want to achieve:

[ { "concert1": { "title": "this is the concerts title", "tickets": [ { "price": 12.99, "seller": { "username": "user1" } }, { "price": 12.99, "seller": { "username": "user1" } } ] } } ]