How to prompt user for photo library change authorization in UIKit?

I am new to programming and iOS development and I am trying to build an onboarding flow for my app.
I would like to ask the user for permission to add images in their photo library when they use the app for the first time.
I have a working code, but it is only fired when the user wants to save their first image and I would like to move the authorization request to the onboarding flow without saving any images.
I don't need access to see the other images in their photo library, just permission to add new images.
I would like to avoid directing the user out of my app to the settings, because this is the first time they will be prompted for authorization.

This is the current working code, but for this code I need an image to be saved:

import UIKit
import PhotosUI

if image != nil {
            PHPhotoLibrary.shared().performChanges({
                PHAssetChangeRequest.creationRequestForAsset(from: image!)}, completionHandler: {success, error in
            })
}

I tried to modify it for the onboarding flow to avoid saving an image at the time of the permission request:

In UIView setup:

button.addTarget(self, action: #selector(askAuthorization), for: .touchUpInside)

Outside of UIView setup:

@objc func askAuthorization() async {
                let status = PHPhotoLibrary.authorizationStatus(for: .addOnly)
                // If the system hasn't determined the user's authorization status, explicitly prompt them for approval.
                if status == .notDetermined {
                    await PHPhotoLibrary.requestAuthorization(for: .addOnly)
                }
            }

The authorization request pops up correctly, but the app crashes due to memory issues immediately after selecting OK.

The authorization request does show up correctly

but immediately after selecting OK the app crashes

Your problem is that you are passing an async action to UIButton.addTarget(_:action:for). Make askAuthorization() synchronous and call the non-async version of the requestAuthorization(for:handler:) method.

@objc func askAuthorization() {
    PHPhotoLibrary.requestAuthorization(for: .addOnly) { status in
        print("status", status.rawValue)
    }
}

Alternatively, you can keep the async version of requestAuthorization(for:handler:) like so:

@objc func askAuthorization() {
    Task {
        await askAuthorizationAsync()
    }
}

func askAuthorizationAsync() async {
    let status = await PHPhotoLibrary.requestAuthorization(for: .addOnly)
    print("status", status.rawValue)
}