Head to head
Which one will break you first?
Two fingerprints on one grid. Both are scored through your profile, so this answers the question for you rather than for the average player.
Age of Empires II: Definitive Edition is the harder of the two for you, by 1.2 points. The gap is widest on strategy, where Age of Empires II: Definitive Edition asks considerably more than Devil May Cry 5. If you want the gentler run, start with Devil May Cry 5.
Axis by axis, biggest gap first
DEVIL MAY CRY 5
You can finish it by mashing. The difficulty lives entirely in the gap between finishing it and playing it, and the game is happy to let you ignore that gap forever.
Real resistance. Expect to work for it.
AGE OF EMPIRES II: DEFINITIVE EDITION
Build orders are the curve, and the campaigns teach almost none of what the game actually asks for. The hard AI does not forget its economy while it fights.
Sustained pressure. Progress is earned.