How do I create a dynamic asset in Orchestrator that looks for an .xlsx file

You have a point there.

The only thing I can think of is if these are two different processes only then the above approach would make sense. But looking at the question, I dont think he has two processes.

@jeff.shubzda the suggestion from @postwick should be your choice.
There are loads of threads in the forum to get the latest file. An example : How do I open the most recent excel file in a folder