I want to create a scrollable background image like this: https://drive.google.com/file/d/1A8FPnpndJskjj-xRye8f1L1_QDSfqHt_/view?usp=sharing

and I want to scroll the image when I start scrolling the cells. I’m using this code to create a UICollectionViewFlowLayout:

func createCollectionView() {
    
    collectionView = UICollectionView(frame: view.bounds, collectionViewLayout: createCompositionalLayout())
    collectionView.autoresizingMask = [.flexibleWidth, .flexibleHeight]
    collectionView.backgroundColor = .gray
    collectionView.isScrollEnabled = false
    view.addSubview(collectionView)
    
    collectionView.register(SectionHeader.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: SectionHeader.reuseIdentifier)
    
    collectionView.register(CarouselCell.self, forCellWithReuseIdentifier: CarouselCell.reuseIdentifier)
    
    createDataSource()
    reloadData()
}

func createCompositionalLayout() -> UICollectionViewLayout {
    let layout = UICollectionViewCompositionalLayout { sectionIndex, layoutEnvironment in
        let section = self.sections[sectionIndex]
        switch section.identifier {
        case "сarouselCell": return self.carouselSection(using: section)
            
        default: return self.carouselSection(using: section)
        }
    }
    
    let config = UICollectionViewCompositionalLayoutConfiguration()
    config.interSectionSpacing = 20
    layout.configuration = config
    
    return layout
}

func carouselSection(using section: Section) -> NSCollectionLayoutSection {
    
    let itemSize = NSCollectionLayoutSize(widthDimension: .fractionalWidth(1.0), heightDimension: .fractionalHeight(1.0))
    let layoutItem = NSCollectionLayoutItem(layoutSize: itemSize)
    
    let a:CGFloat = UIScreen.main.bounds.size.height*0.25
    let h:CGFloat = a * 1.8
    let b:CGFloat = UIScreen.main.bounds.size.height
    
    let layoutGroupSize = NSCollectionLayoutSize(widthDimension: .absolute(b - (h)),
                                                 heightDimension: .absolute(b - (a)))
    
    let layoutGroup = NSCollectionLayoutGroup.horizontal(layoutSize: layoutGroupSize, subitems: [layoutItem])
    
    layoutGroup.contentInsets = NSDirectionalEdgeInsets(top: a, leading: a/10, bottom: 0, trailing: a/10)
    
    let layoutSection = NSCollectionLayoutSection(group: layoutGroup)
    layoutSection.orthogonalScrollingBehavior = .groupPagingCentered
    
    layoutSection.visibleItemsInvalidationHandler = { (items, offset, environment) in
        items.forEach { item in
            let distanceFromCenter = abs((item.frame.midX - offset.x) - environment.container.contentSize.width / 2.0)
            let minScale: CGFloat = 0.7
            let maxScale: CGFloat = 1.1
            let scale = max(maxScale - (distanceFromCenter / environment.container.contentSize.width), minScale)
            item.transform = CGAffineTransform(scaleX: scale, y: scale)
        }
    }
    
    return layoutSection
}

I have this mockup:

But how to do a scrollable background?