It did fix some issues, however, I am afraid that it is not an optimal solution.
Instead of changing the string type, I removed the StringInterop module totally, since we cannot do stackalloc and CoAlloc on other platforms.
You can check my branch https://github.com/sepcnt/MonoGame/tree/desktopvk
It now only left 8 unit tests across multiple platforms and remains full compatibility.

I am now running into some issues with the shader compiler and still waiting for assistance.