How do I put multiple documents/objects into one document/object in MongoDB

I have a list of documents that looks like this:

config: {
    _id: ObjectId('63c6a4b858612f44f37d4771'),
    type: "TypeA",
    priority: 1
}

config: {
    _id: ObjectId('627279d3ba7aef5d6418c867'),
    type: "TypeB",
    priority: 3
}

config: {
    _id: ObjectId('628b4d3ff5b1c1736c0b654a'),
    type: "TypeC",
    priority: 4
}

The type is unique. Is it possible to merge these documents into one document with the type as key of each object field, like this:

TypeA: {
    _id: ObjectId('63c6a4b858612f44f37d4771'),
    priority: 1
},
TypeB: {
    _id: ObjectId('627279d3ba7aef5d6418c867'),
    priority: 3
},
TypeC: {
    _id: ObjectId('628b4d3ff5b1c1736c0b654a'),
    priority: 4
}

I have tried something like this:

{
    $project: {
        newDoc: [ 
            {
                k:'$config.type', 
                v: {
                    id:'$config._id', 
                    priority: '$config.priority'
                }
            }
        ]
    }
}, {
    '$replaceRoot': {
        'newRoot': {
            '$arrayToObject': '$newDoc'
        }
    }
}

That gives me documents that looks like this:

TypeA: {
    _id: ObjectId('63c6a4b858612f44f37d4771'),
    priority: 1
}

TypeB: {
    _id: ObjectId('627279d3ba7aef5d6418c867'),
    priority: 3
}

TypeC: {
    _id: ObjectId('628b4d3ff5b1c1736c0b654a'),
    priority: 4
}

But I need to merge these into one Document…