A small example of using a UIPanGestureRecognizer to swipe up and bring a UICollectionView interaction. This was created as a demo to this StackOverflow question: https://stackoverflow.com/q/71304657/1619193

SwipeCollectionView.swift

//
//  SwipeCollectionView.swift
//  TestApp
//
//  Created by Shawn Frank on 01/03/2022.
//

import UIKit

class SwipeCollectionView: UIViewController
{
    private var collectionView: UICollectionView!
    
    private let imageView = UIImageView()
    
    private let overlayView = UIView()
    
    private let colors: [UIColor] = [.red,
                                     .systemBlue,
                                     .orange,
                                     .systemTeal,
                                     .purple,
                                     .systemYellow]
    
    private var cvBottomAnchor: NSLayoutConstraint?
    
    private var isCarouselShowing = false
    
    private var previousSwipeLocation: CGPoint?
    
    private let cellWidth: CGFloat = 100
    
    private let collectionViewHeight: CGFloat = 185
    
    private let reuseIdentifier = "cell"
    
    lazy var button: UIButton = {
        let button = UIButton(type: .custom)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.setTitleColor(.red, for: .normal)
        button.setTitle("Push", for: .normal)
        button.backgroundColor = .blue
        button.contentHorizontalAlignment = .fill
        button.contentVerticalAlignment = .fill
        button.contentMode = .scaleAspectFill
        button.contentEdgeInsets = UIEdgeInsets(top: .leastNormalMagnitude,
                                                left: .leastNormalMagnitude,
                                                bottom: .leastNormalMagnitude,
                                                right: .leastNormalMagnitude)
        return button
    }()
    
    override func viewDidLoad()
    {
        super.viewDidLoad()
        
        configureNavigationBar()
        configureOverlayView()
        configureCollectionView()
        configureButton()
    }
    
    private func configureButton()
    {
        view.addSubview(button)
        view.addConstraints([
            
            button.centerYAnchor.constraint(equalTo: view.centerYAnchor),
            button.centerXAnchor.constraint(equalTo: view.centerXAnchor)
        
        ])
    }
    
    private func configureNavigationBar()
    {
        title = "Swipe CV"
        
        let appearance = UINavigationBarAppearance()

        // Color of the nav bar background
        appearance.backgroundColor = .white // primary black for you

        navigationController?.navigationBar.standardAppearance = appearance
        navigationController?.navigationBar.scrollEdgeAppearance = appearance
    }
    
    private func configureOverlayView()
    {
        imageView.image = UIImage(named: "dog")
        imageView.translatesAutoresizingMaskIntoConstraints = false
        imageView.contentMode = .scaleAspectFill
        
        overlayView.backgroundColor = .black
        overlayView.translatesAutoresizingMaskIntoConstraints = false
        
        view.addSubview(imageView)
        view.addSubview(overlayView)
        
        // Auto layout pinning the image view and overlay view
        // to the main container view
        view.addConstraints([
        
            imageView.leadingAnchor
                .constraint(equalTo: view.leadingAnchor),
            imageView.topAnchor
                .constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
            imageView.trailingAnchor
                .constraint(equalTo: view.trailingAnchor),
            imageView.bottomAnchor
                .constraint(equalTo: view.bottomAnchor),
            
            overlayView.leadingAnchor
                .constraint(equalTo: view.leadingAnchor),
            overlayView.topAnchor
                .constraint(equalTo: view.safeAreaLayoutGuide.topAnchor),
            overlayView.trailingAnchor
                .constraint(equalTo: view.trailingAnchor),
            overlayView.bottomAnchor
                .constraint(equalTo: view.bottomAnchor)
        
        ])
        
        // We will observe a swipe gesture to check if it is a swipe
        // upwards and then react accordingly
        let swipeGesture = UIPanGestureRecognizer(target: self,
                                                  action: #selector(didSwipe(_:)))
        overlayView.addGestureRecognizer(swipeGesture)
    }
    
    private func configureCollectionView()
    {
        collectionView = UICollectionView(frame: .zero,
                                          collectionViewLayout: createLayout())
        
        collectionView.backgroundColor = .clear
        
        collectionView.register(UICollectionViewCell.self,
                                forCellWithReuseIdentifier: reuseIdentifier)
        
        collectionView.translatesAutoresizingMaskIntoConstraints = false
        
        collectionView.showsHorizontalScrollIndicator = false
        
        // Add some padding for the content on the left
        collectionView.contentInset = UIEdgeInsets(top: 0,
                                                   left: 15,
                                                   bottom: 0,
                                                   right: 0)
        
        collectionView.dataSource = self
        collectionView.delegate = self
        
        overlayView.addSubview(collectionView)
        
        // Collection View should start below the screen
        // We need to persist with this constraint so we can change it later
        
        let bottomAnchor = overlayView.safeAreaLayoutGuide.bottomAnchor
        
        cvBottomAnchor
            = collectionView.bottomAnchor.constraint(equalTo: bottomAnchor,
                                                     constant: collectionViewHeight)
        
        // Collection View starts as hidden and will be animated in swipe up
        collectionView.alpha = 0.0
        
        // Add collection view constraints
        overlayView.addConstraints([
        
            collectionView.leadingAnchor.constraint(equalTo: overlayView.leadingAnchor),
            cvBottomAnchor!,
            collectionView.trailingAnchor.constraint(equalTo: overlayView.trailingAnchor),
            collectionView.heightAnchor.constraint(equalToConstant: collectionViewHeight)
        
        ])
    }
    
    private func createLayout() -> UICollectionViewFlowLayout
    {
        let layout = UICollectionViewFlowLayout()
        layout.scrollDirection = .horizontal
        
        layout.itemSize = CGSize(width: cellWidth, height: collectionViewHeight)
        layout.minimumInteritemSpacing = 20
        
        return layout
    }
    
    @objc
    private func didSwipe(_ gesture: UIGestureRecognizer)
    {
        if !isCarouselShowing
        {
            let currentSwipeLocation = gesture.location(in: view)
            
            if gesture.state == .began
            {
                // record the swipe location when we start the pan gesture
                previousSwipeLocation = currentSwipeLocation
            }
            
            // On swipe continuation, verify the swipe is in the upward direction
            if gesture.state == .changed,
               let previousSwipeLocation = previousSwipeLocation,
               currentSwipeLocation.y < previousSwipeLocation.y
            {
                isCarouselShowing = true
                revealCollectionView()
            }
        }
    }

    // Animate the y position of the collection view and the alpha
    private func revealCollectionView()
    {
        // We need to set the top constraint (y position)
        // to be somewhere above the screen plus some padding
        cvBottomAnchor?.constant = 0 - 75
        
        UIView.animate(withDuration: 0.25) { [weak self] in
            
            // animate change in constraints
            self?.overlayView.layoutIfNeeded()
            
            // reveal the collection view
            self?.collectionView.alpha = 1.0
            
        } completion: { (finished) in
            
            // do something
        }
    }
}

extension SwipeCollectionView: UICollectionViewDataSource
{
    func collectionView(_ collectionView: UICollectionView,
                        numberOfItemsInSection section: Int) -> Int
    {
        return colors.count
    }
    
    func collectionView(_ collectionView: UICollectionView,
                        cellForItemAt indexPath: IndexPath) -> UICollectionViewCell
    {
        let cell
            = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier,
                                                      for: indexPath)
        
        cell.layer.cornerRadius = 20
        cell.clipsToBounds = true
        cell.contentView.backgroundColor = colors[indexPath.item]
        
        return cell
    }
}

extension SwipeCollectionView: UICollectionViewDelegate
{
    func collectionView(_ collectionView: UICollectionView,
                        didSelectItemAt indexPath: IndexPath)
    {
        overlayView.backgroundColor
            = colors[indexPath.item].withAlphaComponent(0.5)
    }
}