Example of self embedded assembly extraction

AssemblyTest.cs

using System.Reflection;
using System.Runtime.Loader;

namespace AssemblyTest
{
    internal class AssemblyTest
    {
        static AssemblyTest()
        {
            SetOurResolveHandlerAtFront();
        }

        private static Assembly AssemblyResolveEventListener(object sender, ResolveEventArgs args)
        {
            if (args is null)
            {
                return null!;
            }
            string name = "AssemblyTest.Resources." + args.Name[..args.Name.IndexOf(',')] + ".dll";
            using Stream? str = Assembly.GetExecutingAssembly().GetManifestResourceStream(name);
            if (str is not null)
            {
                var context = new AssemblyLoadContext(name, false);
                string path = Path.Combine(Directory.GetParent(Assembly.GetExecutingAssembly()?.Location!)!.Parent!.FullName, "UserLibs", args.Name[..args.Name.IndexOf(',')] + ".dll");
                FileStream fstr = new(path, FileMode.Create);
                str.CopyTo(fstr);
                fstr.Close();
                str.Position = 0;

                return context.LoadFromStream(str);
            }
            return null!;
        }
        private static void SetOurResolveHandlerAtFront()
        {
            BindingFlags flags = BindingFlags.Static | BindingFlags.NonPublic;
            FieldInfo? field = null;

            Type domainType = typeof(AssemblyLoadContext);

            while (field is null)
            {
                if (domainType is not null)
                {
                    field = domainType.GetField("AssemblyResolve", flags);
                }
                else
                {
                    return;
                }
                if (field is null)
                    domainType = domainType.BaseType!;
            }

            MulticastDelegate resolveDelegate = (MulticastDelegate)field.GetValue(null)!;
            Delegate[] subscribers = resolveDelegate.GetInvocationList();

            Delegate currentDelegate = resolveDelegate;
            for (int i = 0; i < subscribers.Length; i++)
                currentDelegate = Delegate.RemoveAll(currentDelegate, subscribers[i])!;

            Delegate[] newSubscriptions = new Delegate[subscribers.Length + 1];
            newSubscriptions[0] = (ResolveEventHandler)AssemblyResolveEventListener!;
            Array.Copy(subscribers, 0, newSubscriptions, 1, subscribers.Length);

            currentDelegate = Delegate.Combine(newSubscriptions)!;

            field.SetValue(null, currentDelegate);
        }
    }
}

Just add all DLLs you want to load internally into a folder in your csproject called resources. then set their "Build action" to embedded resource
this method can also be used to use specific assembly versions dynamically as we run before all other assembly resolvers