Why doesn't UICollectionView zIndex work in UICollectionViewLayoutAttributes?

Question

iOS

I'm trying to make the very first cell in the collectionView be behind all the others. Even when the next cell overlaps (floats) a little on the first cell

┌──────────┐ 
│          │ 
│  Cell 0  │ 
│┌─────────┴┐
└┤          │
 │  Cell 4  │
 │          │
 └──────────┘
 ┌──────────┐
 │          │
 │  Cell 5  │
 │          │
 └──────────┘
 ┌──────────┐
 │          │
 │  Cell 6  │
 │          │
 └──────────┘

Tried to add behavior in custom layout via zIndex as follows

Code in custom layout

override func prepare() {
  super.prepare()
  /// Some code
  
  let attributes = UICollectionViewLayoutAttributes(forCellWith: indexPath)
  attributes.zIndex = zIndex
  
  /// Some code
}

Code in cell (cell) collection

override func apply(_ layoutAttributes: UICollectionViewLayoutAttributes) {
    super.apply(layoutAttributes)
    layer.zPosition = CGFloat(layoutAttributes.zIndex)
}

But the desired behavior is not obtained. When reused, the cell first rises to the front position

Tell me who faced such a problem, what I'm doing wrong