head to head
Neither is simply harder - they are hard in different places. Grand Theft Auto V demands more reads; Tomb Raider: The Angel of Darkness demands more optimization.

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

Optimization · Practiced Mastery
A darker stealth-tinged Tomb Raider that sends a fugitive Lara through Paris and Prague.
Grand Theft Auto V leans Execution (Practiced Mastery); Tomb Raider: The Angel of Darkness leans Optimization (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Grand Theft Auto V
Driving and shooting demand decent inputs.
Tomb Raider: The Angel of Darkness
Notoriously stiff controls make precise platforming harder than intended
Grand Theft Auto V leans clearly harder on reads.
Grand Theft Auto V
Online PvP exists but mostly gear/positioning, not modeling.
Tomb Raider: The Angel of Darkness
No adaptive opponents exist
Grand Theft Auto V leans a little harder on variance, though the gap is small.
Grand Theft Auto V
Some mission and lobby randomness.
Tomb Raider: The Angel of Darkness
Levels and puzzles are entirely fixed
Tomb Raider: The Angel of Darkness leans clearly harder on optimization.
Grand Theft Auto V
Heists, money loops, builds learnable.
Tomb Raider: The Angel of Darkness
Puzzle-solving, stat-gated paths, and route knowledge dominate
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.