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

Execution · Practiced Mastery
A modern Gears entry spanning campaign, Horde, Escape, and ranked versus.

Execution · Pure Mechanics
A PS4-era Killzone where a Shadow Marshal and his OWL drone fight through a divided Helghast city.
Gears 5 leans Execution (Practiced Mastery); Killzone Shadow Fall leans Execution (Pure Mechanics).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Gears 5
Movement tech and shotgun duels remain the core test
Killzone Shadow Fall
Standard FPS aim and movement ceiling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Gears 5
Ranked versus rewards out-thinking human opponents
Killzone Shadow Fall
PvP modes reward predicting human players
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Gears 5
Escape and Horde inject some run variance
Killzone Shadow Fall
Some open level routes and spawn noise
Gears 5 leans a little harder on optimization, though the gap is small.
Gears 5
Character ultimates and map control are learnable
Killzone Shadow Fall
OWL drone usage and loadouts optimize cleanly
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.