How to group an array of objects in mongodb

im new to mongodb and Im having some trouble to group an array from a document like this:

_id: ObjectId('5d7afa2609d6ed000dffe1de')
email: "[email protected]"
transactions: [
    {
        "date": "2020-06-10T00:00:00.000+00:00",
        "shares": 100,
        "price": 20,
        "type": "buy",
        "equity_id": "petr4"
    },
    {
        "date": "2020-07-10T00:00:00.000+00:00",
        "shares": 200,
        "price": 10,
        "type": "sell",
        "equity_id": "petr4"
    },
    {
        "date": "2020-06-10T00:00:00.000+00:00",
        "shares": 250,
        "price": 30,
        "type": "buy",
        "equity_id": "vale3"
    }, ...
]

I would like to group these transactions by date and obtain an document like this:

_id: ObjectId('5d7afa2609d6ed000dffe1de')
email: "[email protected]"
transactionsByDay: {
    "2020-06-10": [
        {
            "shares": 100,
            "price": 20,
            "type": "buy",
            "equity_id": "petr4"
        },
        {
            "shares": 250,
            "price": 30,
            "type": "buy",
            "equity_id": "petr4"
        }
    ],
    "2020-07-10": [
        {
            "shares": 200,
            "price": 10,
            "type": "sell",
            "equity_id": "petr4"
        }
    ], ...
}

I tried an aggregation using a group operator but the result didn’t came as expected. Can someone give me a help to solve this?