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

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

Execution · Practiced Mastery
Stick-controlled tennis testing swing timing and percentage shot selection.
Gears 5 leans Execution (Practiced Mastery); Grand Slam Tennis 2 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.
Gears 5
Movement tech and shotgun duels remain the core test
Grand Slam Tennis 2
Total Racket Control stick swings demand precise timing
Gears 5 leans a little harder on reads, though the gap is small.
Gears 5
Ranked versus rewards out-thinking human opponents
Grand Slam Tennis 2
Versus humans, disguising shot placement is genuine prediction
Gears 5 leans a little harder on variance, though the gap is small.
Gears 5
Escape and Horde inject some run variance
Grand Slam Tennis 2
Ball physics are nearly deterministic
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Gears 5
Character ultimates and map control are learnable
Grand Slam Tennis 2
Shot selection and court positioning follow learnable percentages
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.