head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Execution · Practiced Mastery
A character action RPG built on tight parry timing against elaborate scripted bosses.

Execution · Practiced Mastery
A one-hit boss-rush where solving each titan still demands perfect execution.
Stellar Blade leans Execution (Practiced Mastery); Titan Souls leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Stellar Blade
Parry and perfect-dodge timing windows define the ceiling
Titan Souls
One arrow, one hit point; every shot must be perfect
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Stellar Blade
Bosses run fixed movesets, learnable not adaptive
Titan Souls
Bosses are scripted patterns, not adaptive minds
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Stellar Blade
Encounters and loot are static and predictable
Titan Souls
Unknown boss gimmicks only on first attempts
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Stellar Blade
Exospine builds, gear and moveset study reward preparation
Titan Souls
Each titan has a solvable weak-point strategy
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.