Which EDF game is most difficult to solo inferno to the end?

I've played and finish (or almost) the 5 Sandlot games on PS3, PS4 and Vita. In my personal opinion the easiest to hardest are to finish solo, considering on the PS3 and PS4 versions cheesing some classes and missions by playing split screen solo:

- Earth Defense Force 4.1: The Shadow of New Despair

- Earth Defense Force 5

- Earth Defense Force 2025

- Earth Defense Force 2017

- Earth Defense Force 2: Invaders From Planet Space

EDF 4.1 is the easiest. There's no really hard mission with at least 1 class, as at least one is able to solve reasonably easy all of them with well below 2.000 armor, with some missions just being long. Specially for the AR many things that were downright unusable due to slowness in 2025, become problem solvers. The AR is the king of messy missions, the WD of having to sneak and caves ones and the Ranger the sniping ones.

EDF 2025 is honestly not good and becomes really hard due to the slowness and issues. In split screen solo sometimes it's unbearable. Some of the missions are hard, there's almost no missions with NPCs so all enemies always focus on you alone and become a lot harder when you're crawling but your enemies aren't. The foundations of the gameplay are there, but the hardware did not help, and the game was much over what could be done on it (or not optimized enough).

However do see that there isn't a single class in each of the 3 big console games that is able to do without difficulties all missions in inferno. Some missions will always be very to extremely hard for some classes.

The Vita games incomprehensibly were clearly even more than the big console ones developed to be played in coop... Smart option for games for a portable console... They're much harder than the other 3 with EDF 2 being dreadful to solo in inferno with any class and much, much harder than 2017. And being portable games, can't cheese any missions for a class in coop. Any shooting enemy is extremely accurate in both games, and they do massive damage compared to the big consoles games to the point that NPCs are wiped out in a snap. 5-10k armor isn't unreasonable for 2017,  and for 2 well...