During my World of Warcraft days, I used to watch this Machinima Youtube channel where they featured videos of player encounters with bosses and some of the footages didn't have the UI visible. I didn't know how to use machinima (And I still don't (,,Ծ‸Ծ,, )) so I thought it was cool.
I tried to look for anything similar for FFXIV but I've had no luck finding a program to record fights without the UI visible.
A year ago, I shot this video of my character in Crystal tower. To do this, I memorized the commands and skill hotkeys for my bard and hid the UI for the whole fight. Nothing too fancy.
I think it turned out pretty okay. It's almost as if I knew what I was doing