The second pizza wasn't cooking on the top
This is pretty much the theme song for bottom heat scenario ovens.
The wood fired ovens that are suitable for pizza making have relatively wide hearths to allow for a fire next to the baking area. This fire on the side throws off a lot of radiant heat, which browns both the side of the pizza as well as bounces off the ceiling. When burning wood (or charcoal), this side fire scenario is pretty much the only way to achieve Neapolitan bake times. A fire beneath the hearth pretty much trashes your ability to brown the top of the pizza quickly. Theoretically, if the ceiling is low enough, you can try to deflect the heat up and around the hearth and off the ceiling, but that's hard enough to do with the controlled heat of a gas burner and most likely almost impossible to do with burning wood- and this ceiling, as it exists, is way too high. You also have smoke to deal with. Neapolitan pizza gets a slight amount of smokiness from being in a WFO, but it's not baked in the middle of smoke like this pizza would be if you put in a lower ceiling (like the link did with firebricks).
You're talking about taking a very expensive oven that, out of the box, can't really make pizza, but might, with lots of tinkering and additional expense, make something decent. Maybe. I wouldn't bet on it.
If you're going to be tinkering anyway, you might as well invest your time in an LBE. It's incredibly difficult to do Neapolitan with an LBE, but NY style is not that hard, and it will run you about half of what this costs. It won't be as pretty, but it will make great pizza.