UnmanagedExports .net Standard 2.0 package in .net 7.0 not loading Runtime - .net-7.0

Question

I am using the UnmanagedExports.Repack https://github.com/kevingosse/UnmanagedExports.Repack in a .net framework project. It is being upgraded to .net 7.0. However, in 7.0 it always returns "Could not load file or assembly 'System.Runtime, Version=7.0.0.0" whenever an application tries to connect to the DLL.
I got it to work if my dll project is also a .net Standard 2.0. However, I need it in a .net 7.0 project.
I pulled the source code for UnmanagedExports.Repack and upgraded to .net 7.0 (had to add AsssemblyInfo.cs as it was missing). Added references to the projects in my soulution and still give the same error, but the exact code works fine if it is a .net Standard project.
Any ideas on how why I get the "Could not load file or assembly 'System.Runtime, Version=7.0.0.0" error.
*To Reproduce
create a .net standard 2.0 library project and add the DllExample and nuget package UnmanagedExports.Repack. (Make sure the project is set to X64 not any)
add a console application project (I used .net 7.0) add the "Calling Code" classes below.
Run and you get correct results.
remove the .net standard 2.0 library project
Add a .net 7.0 library project, add the DllExample and nuget package UnmanagedExports.Repack (Make sure the project is set to X64 not any)
run in command line and you get the error.*
Dll Exmple:
using System;
using RGiesecke.DllExport;
using System.Runtime.InteropServices;
namespace NewDLLTest2
{
public class DLLCalls
{
[DllExport("TestGetJSON", CallingConvention = CallingConvention.StdCall)]
static public string TestGetJSON()
{
string ret = "{\"Message\":\"Hello\"}";
return ret;
}
}
}
Calling Code:
NativeMethods.cs
using System;
using System.Runtime.InteropServices;
namespace ConsoleApp1
{
class NativeMethods
{
const string _dllLocation = "NewDLLTest2.dll";
[DllImport(_dllLocation, CallingConvention = CallingConvention.StdCall)]
public static extern string TestGetJSON();
}
}
Program.cs
using System;
using System.IO;
namespace ConsoleApp1
{
class Program
{
[STAThread]
static void Main(string[] args)
{
string ret = NativeMethods.TestGetJSON();
Console.WriteLine(ret);
}
}
}