Thanks for the reply. It turns out that this is definitely possible to do...but it's not simple. Here are the steps I took to make the Document Library input dynamic:
First, I used the SharePoint Graph api to get the list of document libraries on my site:

Next I used the Parse JSON action to transform the JSON payload into an array:

Next, I filtered the array down to the element that contains the doc library the user passed in as an input:

where From = body('Transform_Drives_List_JSON_to_Array')?['value'] and the left part of the condition = item()['name']
Next I set a variable with the Id of the document library:

where Value = body('Filter_Drives_Array_on_Document_Library')[0]['Id']
And finally, I used this document library Id in the Document Library Input in the list rows present in a table action:

And with that my flow ran successfully. A lot of steps, but worth it to make the Document Library input dynamic.
P.S. I had to use _api/v2.0/drives because I have multiple document libraries on my site. If I'd only had one library (the default Documents) I could have used _api/v2.0/drive and thus skipped the filter array step to be a hair more efficient.