This is a forum sponsored by Adobe and most users posting here are using Acrobat. Without knowing the 3rd party software vendor I doubt anyone would know were to start.
Have you contacted the 3rdd party that provides this tool about your problem?
Yes, I'm an Adobe CC member using the latest version of Acrobat Pro DC.
I need a document level script that will show/hide text fields based on radio button input (ex. show "Text1" and hide "Text2" when "Choice1" is selected).
I know this is basic, and a mouse up action would be easiest, but it must be a document script.
You can't do it from just a doc-level script. Even if the code was moved to such a script you would still need to call it, which has to be done using a script at the field-level.