On https://docs.unity3d.com/2020.3/Documentation/Manual/windowsstore-plugins-il2cpp.html, it says:

"However, it’s still possible to P/Invoke into these system functions by specifying “**Internal” keyword instead of the DLL name, which results in linker resolving the functions at build time."

It should say:

"However, it’s still possible to P/Invoke into these system functions by specifying “__Internal” keyword instead of the DLL name, which results in linker resolving the functions at build time."

Relevant forum thread: https://forum.unity.com/threads/did-il2cpp-process-change-between-2019-and-2020.1357172