How to properly add .NET Core 3.1 assemblies to PowerShell session?

Related to this question: How to properly add .NET assemblies to Powershell session?

I used this code to likewise try to load a .NET Core 3.1 assembly into a PowerShell session.

I used this code:

# Load Assembly 

Add-Type -Path "I:\DW\tools\bin\Release\netcoreapp3.1\win-x64\publish\DataTools.dll" -PassThru

if ($Error.Count -gt 0) {
    Write-Host $Error[0].Exception.LoaderExceptions
}

and I got this error:

System.IO.FileNotFoundException: Could not load file or assembly 'System.Runtime, Vers ion=4.2.2.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a' or one of its dependenc ies. The system cannot find the file specified.

Then I built my assembly with this command to make it "self-contained":

dotnet publish -r win-x64 -c Release --self-contained

However, now I am getting these LoaderExceptions:

System.TypeLoadException: Could not load type 'System.Object' from assembly 'System.Private.CoreLib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e' because the parent does not exist.

Am I missing something in my dotnet build statement? or do I need to include an additional assembly?

NOTE: I also have dotnet 5 preview installed.