Hi,
Yes, you will be able to build a DLL from a VI in LabVIEW, however, you need the professional version to do that ( https://www.ni.com/en/shop/labview/select-edition.html ) or the "application builder"( https://www.ni.com/en-us/shop/product/labview-application-builder-module.html ).
You will find information on LabVIEW help: application builder >> building a shared library.
I suggest that you use a string as the input of the dll and an array of strings as the output of the dll.
You can use the functions "string to path" and "path to string".
Best regards,