head to head
Neither is simply harder - they are hard in different places. Aero Fighters 3 demands more execution; Grand Theft Auto V demands more reads.

Execution · Practiced Mastery
Memorising scripted bullet waves and executing clean dodges for score.

Execution · Practiced Mastery
Sandbox crime playground spanning shooting, driving, and a persistent online economy.
Aero Fighters 3 leans Execution (Practiced Mastery); Grand Theft Auto V leans Execution (Practiced Mastery).
Aero Fighters 3 leans clearly harder on execution.
Aero Fighters 3
Dodging dense bullet patterns is the whole challenge
Grand Theft Auto V
Driving and shooting demand decent inputs.
Grand Theft Auto V leans clearly harder on reads.
Aero Fighters 3
Enemy waves are fully scripted, nothing adapts
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.
Aero Fighters 3
Minor item drops aside, patterns are fixed once learned
Grand Theft Auto V
Some mission and lobby randomness.
Aero Fighters 3 leans clearly harder on optimization.
Aero Fighters 3
Memorising spawns, routes and ship choice drives high scores
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.