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.

Execution · Practiced Mastery
A basic arcade soccer game testing input timing and simple positioning.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Champions World Class Soccer leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Champions World Class Soccer leans a little harder on execution, though the gap is small.
Champions World Class Soccer
Passing, shooting and tackling timing carry every play
Grand Theft Auto V
Driving and shooting demand decent inputs.
Champions World Class Soccer leans a little harder on reads, though the gap is small.
Champions World Class Soccer
Two-player mode lets you predict a human opponent
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Champions World Class Soccer
Little randomness once team ratings are known
Grand Theft Auto V
Some mission and lobby randomness.
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Champions World Class Soccer
Formation choice and team selection give a known edge
Grand Theft Auto V
Heists, money loops, builds learnable.
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.