head to head
Neither is meaningfully harder - they pose close to the same test. The widest gap is execution, and it is a single point.

Execution · Competitive PvP
An anime fighter testing combo execution and counter-baiting against human opponents.

Execution · Competitive PvP
Fighting-game execution and opponent prediction across an enormous, loosely balanced roster.
Dragon Ball Z: Budokai 3 leans Execution (Competitive PvP); Mortal Kombat: Armageddon leans Execution (Competitive PvP).
Mortal Kombat: Armageddon leans a little harder on execution, though the gap is small.
Dragon Ball Z: Budokai 3
Combo execution, teleport counters and beam timing demand hands
Mortal Kombat: Armageddon
Combo strings and kombat timing decide exchanges
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Dragon Ball Z: Budokai 3
Versus humans, baiting teleports and guessing cancels decides exchanges
Mortal Kombat: Armageddon
Versus humans, baiting and punishing habits is the meta
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Dragon Ball Z: Budokai 3
Almost nothing random beyond minor clash inputs
Mortal Kombat: Armageddon
No hidden information once movesets are known
Mortal Kombat: Armageddon leans a little harder on optimization, though the gap is small.
Dragon Ball Z: Budokai 3
Capsule builds and matchup knowledge underpin competitive play
Mortal Kombat: Armageddon
A 62-character roster of matchup knowledge to internalise
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.