Nested collection views with dynamic content

I am using two nested collection views. I have added the ChildCollectionView to the ParentCollectionViewCell, and ChildCollectionView have 3 cells in it but the ParentCollectionViewCell does not adjust the frame of the cell as per the content.

Here's the code,

ParentCollectionView

class ViewController: UIViewController {
    
    var parentCollectionView: UICollectionView = {
        let _collectionView = UICollectionView.init(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout.init())
        return _collectionView
    }()
    
    let id = "ParentCollectionViewCell"
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view.
        
        view.addSubview(parentCollectionView)
        
        parentCollectionView.translatesAutoresizingMaskIntoConstraints = false
        
        NSLayoutConstraint.activate([
            parentCollectionView.leadingAnchor.constraint(equalTo: view.leadingAnchor),
            parentCollectionView.trailingAnchor.constraint(equalTo: view.trailingAnchor),
            parentCollectionView.topAnchor.constraint(equalTo: view.topAnchor),
            parentCollectionView.bottomAnchor.constraint(equalTo: view.bottomAnchor)
        ])
        
        parentCollectionView.dataSource = self
        
        parentCollectionView.register(UINib(nibName: id, bundle: nil), forCellWithReuseIdentifier: id)
        
        if let flowLayout = parentCollectionView.collectionViewLayout as? UICollectionViewFlowLayout {
            flowLayout.estimatedItemSize = UICollectionViewFlowLayout.automaticSize
        }
    }

}

extension ViewController: UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        1
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: id, for: indexPath) as! ParentCollectionViewCell
        
        cell.backgroundColor = .red
        
        return cell
        
    }
    
}

ParentCollectionViewCell

class ParentCollectionViewCell: UICollectionViewCell {

    var childCollectionView: UICollectionView = {
        let _collectionView = UICollectionView.init(frame: .zero, collectionViewLayout: UICollectionViewFlowLayout.init())
        return _collectionView
    }()
    
    let reuseId = "ChildCollectionViewCell"
    
    private let data = ["ChildCell1","ChildCell2","ChildCell3"]

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
        setupViews()
    }
    
    func setupViews() {
        contentView.addSubview(childCollectionView)

        childCollectionView.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activate([
            childCollectionView.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            childCollectionView.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            childCollectionView.topAnchor.constraint(equalTo: contentView.topAnchor),
            childCollectionView.bottomAnchor.constraint(equalTo: contentView.bottomAnchor),
            childCollectionView.widthAnchor.constraint(equalToConstant: 360)
        ])

        childCollectionView.dataSource = self
        
        childCollectionView.register(UINib(nibName: reuseId, bundle: nil), forCellWithReuseIdentifier: reuseId)
        
        if let flowLayout = childCollectionView.collectionViewLayout as? UICollectionViewFlowLayout {
            flowLayout.estimatedItemSize = UICollectionViewFlowLayout.automaticSize
        }
    }
}

extension ParentCollectionViewCell: UICollectionViewDataSource {
    func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        data.count
    }
    
    func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseId, for: indexPath) as! ChildCollectionViewCell
        
        cell.backgroundColor = .gray
        
        cell.setupViews()
        
        return cell
    }
}

ChildCollectionViewCell

class ChildCollectionViewCell: UICollectionViewCell {
    

    override func awakeFromNib() {
        super.awakeFromNib()
        // Initialization code
    }
    
    func setupViews() {
        
        let label = UILabel()
        
        label.text = "Child Collection"
        
        label.numberOfLines = 0
        
        label.font = label.font.withSize(50)
        
        contentView.addSubview(label)
        
        label.translatesAutoresizingMaskIntoConstraints = false

        NSLayoutConstraint.activate([
            label.leadingAnchor.constraint(equalTo: contentView.leadingAnchor),
            label.trailingAnchor.constraint(equalTo: contentView.trailingAnchor),
            label.topAnchor.constraint(equalTo: contentView.topAnchor),
            label.bottomAnchor.constraint(equalTo: contentView.bottomAnchor)
        ])
        
    }

}

Current Output Current Output

Expected Output Expected Output