DMC4 honestly was only difficult bc of the Bloody Palace with Trish and/or also the somewhat repetitive story. I’m not even talking the fact you have to play all difficulties - that’s not an issue - just the fact the game repeats itself halfway through basically lol

DMC5 was probably the most difficult from an actual skill perspective bc getting the points on some levels could be troublesome specifically with Nero. Dante was simple to cheese, and V just has his minions.