Simple Scrollview created based on UIKit. Can control content offset and scroll direction. Note: to control content offset, set 'scrollOwner' to code.

CustomScrollView.swift

//
//  CustomScrollView.swift
//  BearFitness
//
//  Created by Arutyun Enfendzhyan on 05.10.21.
//

import SwiftUI

struct CustomScrollView: View {
    @Binding var offset: CGFloat
    @Binding var scrollOwner: ScrollOwner
    var axis: Axis = .vertical
    
    let content: AnyView

    var body: some View {
        GeometryReader { proxy in
            Internal(offset: $offset, scrollOwner: $scrollOwner, axis: axis, content: .init(
                Group {
                    switch axis {
                    case .horizontal:
                        content
                            .frame(height: proxy.size.height)
                    case .vertical:
                        content
                            .frame(width: proxy.size.width)
                    }
                }
            ))
        }
    }

    private struct Internal: UIViewControllerRepresentable {
        @Binding var offset: CGFloat
        @Binding var scrollOwner: ScrollOwner
        let axis: Axis
        let content: AnyView

        func makeUIViewController(context: Context) -> UIViewControllerType {
            let controller = UIViewControllerType()
            controller.hostingController.rootView = self.content
            controller.onOffsetChanged = { offset = axis == .vertical ? $0.y : $0.x }
            return controller
        }

        func updateUIViewController(_ controller: UIViewControllerType, context: Context) {
            controller.scrollView.isScrollEnabled = self.scrollOwner == .user
            if self.scrollOwner == .code {
                let offset: CGPoint = {
                    switch axis {
                    case .horizontal:
                        return .init(x: self.offset.atMost(controller.scrollView.contentSize.width).atLeast(0), y: 0)
                    case .vertical:
                        return .init(x: 0, y: self.offset.atMost(controller.scrollView.contentSize.height).atLeast(0))
                    }
                }()
                controller.scrollView.setContentOffset(offset, animated: true)
            } else {
                print("Content offset is controlled by user")
            }
            controller.hostingController.rootView = self.content
            controller.scrollOwner = self.scrollOwner
        }

        class UIViewControllerType: UIViewController, UIScrollViewDelegate {
            lazy var scrollView = UIScrollView()

            var hostingController = UIHostingController(rootView: AnyView(EmptyView()))
            var onOffsetChanged: (CGPoint) -> () = { _ in }
            var scrollOwner: ScrollOwner = .user

            override func viewDidLoad() {
                super.viewDidLoad()
                self.view.addSubview(self.scrollView)
                self.pinEdges(of: self.scrollView, to: self.view)
                
                self.hostingController.willMove(toParent: self)
                self.scrollView.addSubview(self.hostingController.view)
                self.pinEdges(of: self.hostingController.view, to: self.scrollView)
                self.hostingController.didMove(toParent: self)
                self.view.setNeedsUpdateConstraints()
                self.view.updateConstraintsIfNeeded()
                self.view.layoutIfNeeded()
                
                self.scrollView.delegate = self
            }

            func pinEdges(of viewA: UIView, to viewB: UIView) {
                viewA.translatesAutoresizingMaskIntoConstraints = false
                viewB.addConstraints([
                    viewA.leadingAnchor.constraint(equalTo: viewB.leadingAnchor),
                    viewA.trailingAnchor.constraint(equalTo: viewB.trailingAnchor),
                    viewA.topAnchor.constraint(equalTo: viewB.topAnchor),
                    viewA.bottomAnchor.constraint(equalTo: viewB.bottomAnchor),
                ])
            }

            func scrollViewDidScroll(_ scrollView: UIScrollView) {
                if self.scrollOwner == .user {
                    self.onOffsetChanged(scrollView.contentOffset)
                }
            }
        }
    }
}

extension CustomScrollView {
    init<Content: View>(offset: Binding<CGFloat>, scrollOwner: Binding<ScrollOwner>, axis: Axis = .vertical, @ViewBuilder content: () -> Content) {
        self.init(offset: offset, scrollOwner: scrollOwner, axis: axis, content: .init(content()))
    }
}

enum ScrollOwner {
    case user, code
}