Remove multiple packages before build proceeds

Question

I'm trying to delay the build process in Unity when building locally. Before building I want to remove some packages via the Client.Remove method in a prebuild script. The build should only continue after the packages were removed.

The Prebuild class looks like this:

#if UNITY_EDITOR
using System;
using System.Collections.Generic;
using UnityEditor;
using UnityEditor.Build;
using UnityEditor.Build.Reporting;
using UnityEditor.PackageManager.Requests;
using UnityEditor.PackageManager;
using UnityEngine;

[Serializable]
public class PreBuildProcessor : IPreprocessBuildWithReport {

    [SerializeField] private static RemoveRequest request;

    [SerializeField] private Queue<string> packages = new Queue<string>();


    public int callbackOrder { get { return 0; } }

    public void OnPreprocessBuild(BuildReport report) {
        Debug.Log("Removing unused scripts...");
        RemovePackages();
    }

    private void RemovePackages() {
#if !ADS_ENABLED
        packages.Enqueue("com.unity.ads");
#endif

#if !ANALYTICS_ENABLED
        packages.Enqueue("com.unity.analytics");
#endif

#if !IAP_ENABLED
        packages.Enqueue("com.unity.purchasing");
#endif

#if !REVIEW_ENABLED
        packages.Enqueue("com.google.play.review");
#endif

#if !NOTIFICATIONS_ENABLED
        packages.Enqueue("com.unity.mobile.notifications");
#endif


        if (packages.Count != 0) {
            request = Client.Remove(packages.Dequeue());
            EditorApplication.update += PackageRemovalProgress;
        }
    }

    private void PackageRemovalProgress() {
        Debug.Log("Removing....");
        if (request.IsCompleted) {
            switch (request.Status) {
            case StatusCode.Failure:    // couldn't remove package
                Debug.LogError("Couldn't remove package '" + request.PackageIdOrName + "': " + request.Error.message);
                break;
    
            case StatusCode.InProgress:
                break;
    
            case StatusCode.Success:
                Debug.Log("Removed package: " + request.PackageIdOrName);
                break;
            }
    
            if (packages.Count > 0) {
                var nextRequestStr = packages.Dequeue();
                Debug.Log("Requesting removal of '" + nextRequestStr + "'.");
                request = Client.Remove(nextRequestStr);
            } else {    // no more packages to remove
                EditorApplication.update -= PackageRemovalProgress;
            }
        }

        return;
    }

}

#endif

The first two packages are removed and the "Removed Package" log message is printed into the console. The third package is removed but I don't get a log message. The last two packages are not removed at all and I don't get any notification or log that anything failed.

Is there any way to delay the build until all packages are removed?