head to head
Neither is simply harder - they are hard in different places. Fallout: New Vegas demands more execution; War for the Overworld demands more reads.

Optimization · Pure Optimization
A faction-driven RPG-shooter where build and route planning shape every ending.

Optimization · Pure Optimization
A Dungeon Keeper successor about building an evil lair and crushing do-gooders.
Fallout: New Vegas leans Optimization (Pure Optimization); War for the Overworld leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
War for the Overworld
Mouse-driven dungeon management; light APM demand
War for the Overworld leans clearly harder on reads.
Fallout: New Vegas
Scripted factions and enemies
War for the Overworld
Skirmish humans adapt; campaign AI is scripted
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Some loot and crit RNG
War for the Overworld
Enemy dungeon layout hidden until scouted
Same score on optimization - which means the number cannot separate them. The difference is in what each one asks of you.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
War for the Overworld
Room economy, minion synergy, and build order 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.