I found a workaround in between of what you mentioned.
I'm using a free Hubspot form that accepts multiple files. Thus, at the end of my Guided Track program, I redirect the user to the form and pass the user variables via REST to Hubspot so I can relate the file with the response.
I'm doing this at the end of the program because it's better for my workflow. It might be possible to also return to guided track if necessary, but I didn't try.