I have a question if you can answer me it will delight me. How do you enable the touch screen keyboard? Is it inside the XR Interaction Toolkit? I have no clue or whatsoever to get that touch keyboard out and use it in a input field in Unity.
Usually the touchscreen keyboard opens up on its own when you click on an InputField.
However if it doesn't, you should be able to open it manually like this in C#
public void OpenKeyboard()
{
TouchScreenKeyboard.Open("");
}
You can learn more about the touchscreen keyboard and its properties right here.
Hope this helped you :)