Environment
Pythonnet version: 3.0.0a2 PRE-RELEASE
Python version: 3.10.5
Operating System: Windows 10
.NET Runtime: .Net core 6.0 and 5.0
Details
Have created a simple program to

Add 2 numbers
Read XML from File
Convert Base64 Encode
Used PythonNet CLR to import the dll and access all the above methods

On .NET core 6.0:

Add 2 numbers worked like charm
Read XML and Covert Base64 threw error
System.TypeLoadException: Could not load type 'System.Text.Encoding' from assembly 'System.Text.Encoding, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.
at DllExport.XMLReader(String filePath)

On .NET core 5.0 :
Add 2 numbers worked
Read XML worked
Convert Base64 did not work and threw error
System.TypeLoadException: Could not load type 'System.Convert' from assembly 'System.Runtime, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.
at ReusableLibariesConsole.Program.Base64_Encode(Byte[] data)
We have set the .NET version to 2.0
then all 3 errors disappeared however further methods such as Encryption did not work again
System.TypeLoadException: Could not load type 'System.Security.Cryptography.PasswordDeriveBytes' from assembly 'System.Security.Cryptography.Csp, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.
at DllExport.EncryptionManagerClass.Encrypt(String inputData, String password, Int32 bits)
We tried lot of fixes such as setting CPU to x64, changing target framework and nothing worked.
Please let us know if you need further information
I happened to have been battling with a similar issue about a week ago
with the error: System.TypeLoadException: Could not load type 'System.Data.Dataset' form assembly 'System.Data.Common', Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
To resolved this I downgraded the .NET version to 4.8
Load C# from Python: Unable to Load the .NET dependencies while accessing the methods