head to head
Neither is simply harder - they are hard in different places. Fallout: New Vegas demands more execution; The Universim demands more variance.

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

Optimization · Pure Optimization
A god game testing civilisation resource planning against semi-autonomous citizens and random disasters.
Fallout: New Vegas leans Optimization (Pure Optimization); The Universim leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
The Universim
God-hand clicking has no dexterity ceiling
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
The Universim
Autonomous nugget AI wanders but never models you
The Universim leans clearly harder on variance.
Fallout: New Vegas
Some loot and crit RNG
The Universim
Random disasters and AI whims disrupt plans
Fallout: New Vegas leans a little harder on optimization, though the gap is small.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
The Universim
Research pacing, resource balance, and intervention timing are the game
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.