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.

Optimization · Pure Optimization
Linear JRPG built around real-time paradigm switching and stagger combat.

Optimization · Pure Optimization
A perk-driven sci-fi RPG won by flaw selection and dialogue routing.
Final Fantasy XIII leans Optimization (Pure Optimization); The Outer Worlds leans Optimization (Pure Optimization).
The Outer Worlds leans a little harder on execution, though the gap is small.
Final Fantasy XIII
Paradigm shifts need timely menu reactions
The Outer Worlds
FPS-lite with time-dilation aim
The Outer Worlds leans a little harder on reads, though the gap is small.
Final Fantasy XIII
Scripted stagger-phase bosses
The Outer Worlds
Scripted enemies
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Final Fantasy XIII
Minor randomness in enemy actions
The Outer Worlds
Loot rolls, dialogue check variance
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Final Fantasy XIII
Paradigm sequencing and stagger timing are solvable
The Outer Worlds
Perks, flaws, dialogue routing rewarded
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.