head to head
Neither is harder. They score identically on all four axes, so the difference between them is in kind, not degree.

Optimization · Pure Optimization
Optimizing city placement, social policies, and victory routing under randomized map unknowns.

Optimization · Pure Optimization
Racing to secure relics and optimize unit upgrade chains in a hostile hex-grid wargame.
Civilization V leans Optimization (Pure Optimization); Warhammer 40,000: Gladius - Relics of War leans Optimization (Pure Optimization).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Civilization V
UI actions need no precision; speed is not a factor
Warhammer 40,000: Gladius - Relics of War
Hex turn-based; no physical precision ceiling
Same score on reads - which means the number cannot separate them. The difference is in what each one asks of you.
Civilization V
AI follows scripted personalities, not genuine player modelling
Warhammer 40,000: Gladius - Relics of War
AI factions follow fixed expansion doctrines without adaptive modelling
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Civilization V
Random starts, barbarian spawns, and goody huts create hidden unknowns
Warhammer 40,000: Gladius - Relics of War
Random relic placement and event spawns add meaningful hidden unknowns
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Civilization V
Hex placement, social policies, and victory routing are fully solvable
Warhammer 40,000: Gladius - Relics of War
Unit upgrade routing and resource building sequencing are deeply solvable
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.