(Don’t know if the use of “workflow” in your post refers to lowercase-w “workflow” in a general sense or the capital-W Workflow app for iOS now called Shortocuts)
To play cloud-based playlists there are any number of apps that can do that - here are two older articles listing some iOS apps, most of which are still around.
I’m not sure what workflow you want to create: what do you want to do besides play files in a folder - upload files? Rename?
I want to be able to have a series of audio files to play one after another off a Siri shortcut (voice command).
The reason I want to do these as separate files versus one large one which (I already know how to do this with just a single file) is that they will change frequently and having multiple files I make it easy to keep up to date.