I stiil prefer playing through duty finder at my stage in the game, minus the learning setting. (nowhere near endgame yet) The first time I did Ifrit I mentioned it being completely new to the Trial. I remember not seeing the nail because silly me didn't zoom the camera out far enough and kept right on attacking Ifrit. Moments later the whole party wiped. I had no idea why until someone simply told me to attack the protruding nail, with no reprimand. We went for the second attempt and obliterated Ifrit in minutes.

To be frank, if I wanted to learn a particular run before attempting with Duty Finder (or skipping DF altogether), I would make a party finder for said Dungeon/Trial and mention that it's a learning/training run. I agree that sometimes you can watch a video until you're red in the eyes, but once you get in the dungeon nervousness takes over and you forget everything you watched and wind up struggling due to fear. Now that's a problem that only actual experience can overcome, imo. Some people learn best by doing. That's how it's always been for me, both when it comes to games and real life even.