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

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

Optimization · Pure Optimization
Growing a floating base by solving resource chains and research order against scripted ocean threats.
Fallout: New Vegas leans Optimization (Pure Optimization); Raft leans Optimization (Pure Optimization).
Fallout: New Vegas leans clearly harder on execution.
Fallout: New Vegas
Shooter inputs with VATS assist
Raft
Shark hook-attacks require minimal timing
Fallout: New Vegas leans a little harder on reads, though the gap is small.
Fallout: New Vegas
Scripted factions and enemies
Raft
Shark and seagull AI are scripted with no player modelling
Raft leans clearly harder on variance.
Fallout: New Vegas
Some loot and crit RNG
Raft
Island loot tables and resource drift introduce randomness
Fallout: New Vegas leans a little harder on optimization, though the gap is small.
Fallout: New Vegas
Faction routing, perks, builds heavily rewarded
Raft
Raft expansion, food chains, and research order are solvable systems
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.