head to head
Hardware: Rivals asks more than Grand Theft Auto V, and the gap is reads.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.

Execution · Competitive PvP
Vehicular arena duels of handling and aim against human drivers.
Grand Theft Auto V leans Execution (Practiced Mastery); Hardware: Rivals leans Execution (Competitive PvP).
Hardware: Rivals leans a little harder on execution, though the gap is small.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Hardware: Rivals
Vehicle handling and turret aim decide most duels
Hardware: Rivals leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Hardware: Rivals
Human opponents' arena rotations reward some prediction
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto V
Some mission and lobby randomness.
Hardware: Rivals
Pickup spawns add mild positional randomness
Grand Theft Auto V leans a little harder on optimization, though the gap is small.
Grand Theft Auto V
Heists, money loops, builds learnable.
Hardware: Rivals
Weapon-pickup control and map knowledge underpin wins
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.