SMT V's main story is pretty average difficulty, almost too easy if you know the combat system and do any real prep with fusions. The optional content can be very challenging, though.
P5R does have similar requirements to get the true ending, but they're pretty easy to meet if you make any real effort with keeping Confidants leveled. There are three Confidant requirements you need to meet to have access to the true ending and Royal's extra content.
If you want to see all of the extra content for Royal, then you need to have all three. Which is exactly what I said in the first place.
Um, ack shoe wally!